/*	$Id: Class1Send.c++,v 1.81 2005/11/29 21:42:13 lhoward Exp $ */
/*
 * Copyright (c) 1990-1996 Sam Leffler
 * Copyright (c) 1991-1996 Silicon Graphics, Inc.
 * HylaFAX is a trademark of Silicon Graphics
 *
 * Permission to use, copy, modify, distribute, and sell this software and 
 * its documentation for any purpose is hereby granted without fee, provided
 * that (i) the above copyright notices and this permission notice appear in
 * all copies of the software and related documentation, and (ii) the names of
 * Sam Leffler and Silicon Graphics may not be used in any advertising or
 * publicity relating to the software without the specific, prior written
 * permission of Sam Leffler and Silicon Graphics.
 * 
 * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND, 
 * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY 
 * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.  
 * 
 * IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR
 * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
 * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
 * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF 
 * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE 
 * OF THIS SOFTWARE.
 */

/*
 * EIA/TIA-578 (Class 1) Modem Driver.
 *
 * Send protocol.
 */
#include "Sys.h"
#include "Class1.h"
#include "ModemConfig.h"
#include "HDLCFrame.h"
#include "t.30.h"

/*
 * Force the tty into a known flow control state.
 */
bool
Class1Modem::sendSetup(FaxRequest& req, const Class2Params& dis, fxStr& emsg)
{
    if (flowControl == FLOW_XONXOFF)
	setXONXOFF(FLOW_NONE, FLOW_NONE, ACT_FLUSH);
    return (FaxModem::sendSetup(req, dis, emsg));
}

/*
 * Wait-for and process a dial command response.
 */
CallStatus
Class1Modem::dialResponse(fxStr& emsg)
{
    // This is as good a time as any, perhaps, to reset modemParams.br.
    // If the call does V.8 handshaking, then it will be altered.
    modemParams.br = nonV34br;

    int ntrys = 0;
    ATResponse r;
    do {
	r = atResponse(rbuf, conf.dialResponseTimeout);
	
	/*
	 * Blacklisting is handled internally just like a NOCARRIER.
	 * emsg is customized to let the user know the problem lies in
	 * the modem and not in line conditions, cables ...
	 * The known blacklisting modem responses are:
	 * 1. "BLACKLISTED"
	 * 2. "DELAYED HH:MM:SS" (ie: "DELAYED 00:59:02")
	 * 3. "DIALING DISABLED" (USR)
	 * User can switch on/off the modem or use appropriate reset commands
	 * to clear/disable blacklisted numbers, ie:
	 * ModemResetCmds: AT%TCB  (Some rockwell chipsets)
	 * ModemResetCmds: AT%D0   (Some topic chipsets)
	 * ModemResetCmds: ATS40=7 (Some usr chipsets)
	 */
	if (strncmp(rbuf, "BLACKLISTED", 11) == 0
		|| strncmp(rbuf, "DELAYED", 7) == 0
		|| strncmp(rbuf, "DIALING DISABLED", 16) == 0) {
	    emsg = "Blacklisted by modem";
	    return (NOCARRIER);
	}

	switch (r) {
	case AT_ERROR:	    return (ERROR);	// error in dial command
	case AT_BUSY:	    return (BUSY);	// busy signal
	case AT_NOCARRIER:  return (NOCARRIER);	// no carrier detected
	case AT_OK:	    return (NOCARRIER);	// (for AT&T DataPort)
	case AT_NODIALTONE: return (NODIALTONE);// local phone connection hosed
	case AT_NOANSWER:   return (NOANSWER);	// no answer or ring back
	case AT_TIMEOUT:    return (FAILURE);	// timed out w/o response
	case AT_CONNECT:    return (OK);	// fax connection
	case AT_FCERROR:
	    /*
	     * Some modems that support adaptive-answer assert a data
	     * carrier first and then fall back to answering as a fax
	     * modem.  For these modems we'll get an initial +FCERROR
	     * (wrong carrier) result that we ignore.  We actually
	     * accept three of these in case the modem switches carriers
	     * several times (haven't yet encountered anyone that does).
	     */
	    if (++ntrys == 3) {
		emsg = "Ringback detected, no answer without CED"; // XXX
		protoTrace(emsg);
		return (NOFCON);
	    }
	    break;
	}
    } while (r == AT_OTHER && isNoise(rbuf));
    return (FAILURE);
}

void
Class1Modem::sendBegin()
{
    FaxModem::sendBegin();
    setInputBuffering(false);
    // polling accounting?
    params.br = (u_int) -1;			// force initial training
}

#define BATCH_FIRST 1
#define BATCH_LAST  2

/*
 * Get the initial DIS command.
 */
FaxSendStatus
Class1Modem::getPrologue(Class2Params& params, bool& hasDoc, fxStr& emsg, u_int& batched)
{
    u_int t1 = howmany(conf.t1Timer, 1000);		// T1 timer in seconds
    time_t start = Sys::now();
    HDLCFrame frame(conf.class1FrameOverhead);

    if (useV34 && (batched & BATCH_FIRST))
	waitForDCEChannel(true);		// expect control channel

    bool framerecvd = false;
    if (batched & BATCH_FIRST)			// receive carrier raised
	framerecvd = recvFrame(frame, FCF_SNDR, conf.t2Timer, true);
    else {					// receive carrier not raised
	// The receiver will allow T2 to elapse intentionally here.
	// To keep recvFrame from timing out we double our wait.
	framerecvd = recvFrame(frame, FCF_SNDR, conf.t2Timer * 2);
    }

    for (;;) {
	if (gotEOT) break;
	if (framerecvd) {
	    /*
	     * An HDLC frame was received; process any
	     * optional frames that precede the DIS.
	     */
	    do {
		switch (frame.getRawFCF()) {
		case FCF_NSF:
                    recvNSF(NSF(frame.getFrameData(), frame.getFrameDataLength()-1, frameRev));
		    break;
		case FCF_CSI:
		    { fxStr csi; recvCSI(decodeTSI(csi, frame)); }
		    break;
		case FCF_DIS:
		    dis_caps = frame.getDIS();
		    params.setFromDIS(dis_caps);
		    curcap = NULL;			// force initial setup
		    if (useV34 && params.ec == EC_DISABLE) {
			protoTrace("V.34-Fax session, but DIS signal contains no ECM bit; ECM forced.");
			params.ec = EC_ENABLE256;
		    }
		    break;
		}
	    } while (frame.moreFrames() && recvFrame(frame, FCF_SNDR, conf.t2Timer));
	    if (frame.isOK()) {
		switch (frame.getRawFCF()) {
		case FCF_DIS:
		    hasDoc = dis_caps.isBitEnabled(FaxParams::BITNUM_T4XMTR);// documents to poll?
		    if (!dis_caps.isBitEnabled(FaxParams::BITNUM_T4RCVR)) {
			emsg = "Remote has no T.4 receiver capability";
			protoTrace(emsg);
		    	if (! hasDoc)	// don't die if we can poll
			    return (send_failed);
		    }
		    return (send_ok);
		case FCF_DTC:				// NB: don't handle DTC
		    emsg = "DTC received when expecting DIS (not supported)";
		    break;
		case FCF_DCN:
		    emsg = "COMREC error in transmit Phase B/got DCN";
		    break;
		default:
		    emsg = "COMREC invalid command received/no DIS or DTC";
		    break;
		}
		protoTrace(emsg);
		return (send_retry);
	    }
	}
	/*
	 * This delay is only supposed to be done if the signal
	 * is gone (see p.105 of Rec. T.30).  We just assume
	 * it rather than send a command to the modem to check.
	 * Getting NO CARRIER after EOM seems necessary, so we
	 * usually do this at least twice before any HDLC frames
	 * are received.  Using +FTS may be better than looping,
	 * but many modems won't support that.
	 */
	if (!useV34) pause(200);
	/*
	 * Wait up to T1 for a valid DIS.
	 */
	if ((unsigned) Sys::now()-start >= t1)
	    break;
	framerecvd = recvFrame(frame, FCF_SNDR, conf.t2Timer);
    }
    emsg = "No answer (T.30 T1 timeout)";
    protoTrace(emsg);
    return (send_retry);
}

/*
 * Setup file-independent parameters prior
 * to entering Phase B of the send protocol.
 */
void
Class1Modem::sendSetupPhaseB(const fxStr& p, const fxStr& s)
{
    if (p != fxStr::null && dis_caps.isBitEnabled(FaxParams::BITNUM_PWD))
	encodePWD(pwd, p);
    else
	pwd = fxStr::null;
    if (s != fxStr::null && dis_caps.isBitEnabled(FaxParams::BITNUM_SUB))
	encodePWD(sub, s);
    else
	sub = fxStr::null;
}

const u_int Class1Modem::modemPFMCodes[8] = {
    FCF_MPS,		// PPM_MPS
    FCF_EOM,		// PPM_EOM
    FCF_EOP,		// PPM_EOP
    FCF_EOP,		// 3 ??? XXX
    FCF_PRI_MPS,	// PPM_PRI_MPS
    FCF_PRI_EOM,	// PPM_PRI_EOM
    FCF_PRI_EOP,	// PPM_PRI_EOP
    FCF_EOP,		// 7 ??? XXX
};

bool
Class1Modem::decodePPM(const fxStr& pph, u_int& ppm, fxStr& emsg)
{
    if (FaxModem::decodePPM(pph, ppm, emsg)) {
	ppm = modemPFMCodes[ppm];
	return (true);
    } else
	return (false);
}

/*
 * Send the specified document using the supplied
 * parameters.  The pph is the post-page-handling
 * indicators calculated prior to initiating the call.
 */
FaxSendStatus
Class1Modem::sendPhaseB(TIFF* tif, Class2Params& next, FaxMachineInfo& info,
    fxStr& pph, fxStr& emsg, u_int& batched)
{
    int ntrys = 0;			// # retraining/command repeats
    bool morePages = true;		// more pages still to send
    HDLCFrame frame(conf.class1FrameOverhead);

    do {
        hadV34Trouble = false;		// to monitor failure type
        hadV17Trouble = false;		// to monitor failure type
	batchingError = false;
	signalRcvd = 0;
	if (abortRequested())
	    return (send_failed);
	if (repeatPhaseB) {
	    /*
	     * We need to repeat protocol from the beginning of Phase B
	     * due to a non-batched EOM signal (formatting change).
	     */
	    params.br = (u_int) -1;		// force retraining
	    batched = batched & ~BATCH_FIRST;	// must raise V.21 receive carrier
	    bool hasDoc;
	    FaxSendStatus status = getPrologue(params, hasDoc, emsg, batched);
	    if (status != send_ok) return (send_retry);
	    repeatPhaseB = false;
	}
	/*
	 * Check the next page to see if the transfer
	 * characteristics change.  If so, update the
	 * T.30 session parameters and do training.
	 * Note that since the initial parameters are
	 * setup to be "undefined", training will be
	 * sent for the first page after receiving the
	 * DIS frame.
	 */
	if (params != next) {
	    if (!sendTraining(next, 3, emsg)) {
		if (hadV34Trouble) {
		    protoTrace("The destination appears to have trouble with V.34-Fax.");
		    return (send_v34fail);
		}
		if (hadV17Trouble) {
		    protoTrace("The destination appears to have trouble with V.17.");
		    return (send_v17fail);
		}
		if (!(batched & BATCH_FIRST)) {
		    protoTrace("The destination appears to not support batching.");
		    return (send_batchfail);
		}
		return (send_retry);
	    }
	    params = next;
	}

	if (params.ec == EC_DISABLE) {		// ECM does it later
	    /*
	     * According to T.30 5.3.2.4 we must pause at least 75 ms "after 
	     * receipt of a signal using the T.30 binary coded modulation" and 
	     * "before sending any signals using V.27 ter/V.29/V.33/V.17 
	     * modulation system"
	     */
	    pause(conf.class1SendMsgDelay);
	}

	/*
	 * The ECM protocol needs to know PPM, so this must be done beforehand...
	 */
	morePages = !TIFFLastDirectory(tif);
	u_int cmd;
	if (!decodePPM(pph, cmd, emsg))
	    return (send_failed);
	/*
	 * If pph tells us that the PPM is going to be EOM it means that the
	 * next page is formatted differently from the current page.  To handle this
	 * situation properly, EOM is used.  Following EOM we must repeat the
	 * entire protocol of Phase B.  This triggers that.  Batching is handled
	 * also with EOM, but not with the repeatPhaseB flag.
	 */
	repeatPhaseB = (cmd == FCF_EOM);
	if (cmd == FCF_EOP && !(batched & BATCH_LAST))
	    cmd = FCF_EOM;

	/*
	 * Transmit the facsimile message/Phase C.
	 */
	if (!sendPage(tif, params, decodePageChop(pph, params), cmd, emsg)) {
	    if (hadV34Trouble) {
		protoTrace("The destination appears to have trouble with V.34-Fax.");
		return (send_v34fail);
	    }
	    if (batchingError && (batched & BATCH_FIRST)) {
		protoTrace("The destination appears to not support batching.");
		return (send_batchfail);
	    }
	    return (send_retry);	// a problem, disconnect
	}

	int ncrp = 0;

	if (params.ec == EC_DISABLE) {
	    /*
	     * Delay before switching to the low speed carrier to
	     * send the post-page-message frame according to 
	     * T.30 chapter 5 note 4.  We provide for a different
	     * setting following EOP because, empirically, some 
	     * machines may need more time. Beware that, reportedly, 
	     * lengthening this delay too much can permit echo 
	     * suppressors to kick in with bad results.
	     *
	     * Historically this delay was done using a software pause
	     * rather than +FTS because the time between +FTS and the 
	     * OK response is longer than expected, and this was blamed
	     * for timing problems.  However, this "longer than expected"
	     * delay is a result of the time required by the modem's
	     * firmware to actually release the carrier.  T.30 requires
	     * a delay (period of silence), and this cannot be guaranteed
	     * by a simple pause.  +FTS must be used.
	     */
	    if (!atCmd(cmd == FCF_MPS ? conf.class1PPMWaitCmd : conf.class1EOPWaitCmd, AT_OK)) {
		emsg = "Stop and wait failure (modem on hook)";
		protoTrace(emsg);
		return (send_retry);
	    }
	}

	do {
	    u_int ppr;
	    if (signalRcvd == 0) {
		/*
		 * Send post-page message and get response.
		 */
		if (!sendPPM(cmd, frame, emsg)) {
		    if (cmd == FCF_EOM && (batched & BATCH_FIRST)) {
			protoTrace("The destination appears to not support batching.");
			return (send_batchfail);
		    }
		    return (send_retry);
		}
		ppr = frame.getFCF();
		tracePPR("SEND recv", ppr);
	    } else {
		// ECM protocol already got post-page response
		ppr = signalRcvd;
	    }
	    switch (ppr) {
	    case FCF_RTP:		// ack, continue after retraining
		params.br = (u_int) -1;	// force retraining above
		/* fall thru... */
	    case FCF_MCF:		// ack confirmation
	    case FCF_PIP:		// ack, w/ operator intervention
		countPage();		// bump page count
		notifyPageSent(tif);	// update server
		if (pph[2] == 'Z')
		    pph.remove(0,2+5+1);// discard page-chop+handling info
		else
		    pph.remove(0,3);	// discard page-handling info
		if (params.ec == EC_DISABLE) atCmd(conf.class1SwitchingCmd, AT_OK);
		ntrys = 0;
		if (morePages) {	// meaning, more pages in this file, but there may be other files
		    if (!TIFFReadDirectory(tif)) {
			emsg = "Problem reading document directory";
			protoTrace(emsg);
			return (send_failed);
		    }
		}
		if (cmd != FCF_EOP) {
		    if (ppr == FCF_PIP) {
			emsg = "Procedure interrupt (operator intervention)";
			protoTrace(emsg);
			return (send_failed);
		    }
		    if (ppr == FCF_MCF && !repeatPhaseB) {
			/*
			 * The session parameters cannot change except following
			 * the reception of an RTN or RTP signal or the transmission
			 * of an EOM signal.
			 *
			 * Since we did not receive RTN or RTP, if EOM was not used
			 * (repeating from the start of Phase B) then we require that
			 * the next page have the same characteristics as this page.
			 */
			next = params;
		    }
		}
		break;
	    case FCF_DCN:		// disconnect, abort
		emsg = "Remote fax disconnected prematurely";
		protoTrace(emsg);
		return (send_retry);
	    case FCF_RTN:		// nak, retry after retraining
                switch( conf.rtnHandling ){
		case RTN_RETRANSMITIGNORE:
		    if (ntrys < 2) break;
                case RTN_IGNORE:
			// ignore error and try to send next page
			// after retraining
		    params.br = (u_int) -1;	// force retraining above
		    countPage();		// bump page count
		    notifyPageSent(tif);	// update server
		    if (pph[2] == 'Z')
			pph.remove(0,2+5+1);// discard page-chop+handling info
		    else
			pph.remove(0,3);	// discard page-handling info
		    ntrys = 0;
		    if (ppr == FCF_PIP) {
			emsg = "Procedure interrupt (operator intervention)";
			protoTrace(emsg);
			return (send_failed);
		    }
		    if (morePages) {
			if (!TIFFReadDirectory(tif)) {
			    emsg = "Problem reading document directory";
			    protoTrace(emsg);
			    return (send_failed);
			}
			FaxSendStatus status =
			    sendSetupParams(tif, next, info, emsg);
			if (status != send_ok)
			    return (status);
		    }
		    continue;
                case RTN_GIVEUP:
                    emsg = "Unable to transmit page"
                        " (giving up after RTN)";
		    protoTrace(emsg);
                    return (send_failed); // "over and out"
                }
                // case RTN_RETRANSMIT
                if (++ntrys >= 3) {
                    emsg = "Unable to transmit page"
                        " (giving up after 3 attempts)";
		    protoTrace(emsg);
                    return (send_retry);

                }
		params.br = (u_int) -1;	// force training
		if (!dropToNextBR(next)) {
                    emsg = "Unable to transmit page"
                        " (NAK at all possible signalling rates)";
		    protoTrace(emsg);
                    return (send_retry);
		}
                morePages = true;	// retransmit page
		break;
	    case FCF_PIN:		// nak, retry w/ operator intervention
		emsg = "Unable to transmit page"
		       " (NAK with operator intervention)";
		protoTrace(emsg);
		return (send_failed);
	    case FCF_CRP:
		if (!useV34 && !atCmd(conf.class1SwitchingCmd, AT_OK)) {
		    emsg = "Failure to receive silence.";
		    protoTrace(emsg);
		    return (send_retry);
		}
		break;
	    default:			// unexpected abort
		emsg = "Fax protocol error (unknown frame received)";
		protoTrace(emsg);
		return (send_retry);
	    }
	} while (frame.getFCF() == FCF_CRP && ++ncrp < 3);
	if (ncrp == 3) {
	    emsg = "Fax protocol error (command repeated 3 times)";
	    protoTrace(emsg);
	    return (send_retry);
	}
    } while (morePages);
    if (hadV17Trouble) return (send_v17fail);
    return (send_ok);
}

/*
 * Send ms's worth of zero's at the current signalling rate.
 * Note that we send real zero data here as recommended
 * by T.31 8.3.3 rather than using the Class 1 modem facility
 * to do zero fill.
 */
bool
Class1Modem::sendTCF(const Class2Params& params, u_int ms)
{
    u_int tcfLen = params.transferSize(ms);
    u_char* tcf = new u_char[tcfLen];
    memset(tcf, 0, tcfLen);
    bool ok = transmitData(curcap->value, tcf, tcfLen, frameRev, true);
    delete tcf;
    return ok;
}

/*
 * Send the training prologue frames:
 *     PWD	password (optional)
 *     SUB	subaddress (optional)
 *     TSI	transmitter subscriber id
 *     DCS	digital command signal
 */
bool
Class1Modem::sendPrologue(FaxParams& dcs_caps, const fxStr& tsi)
{
    /*
     * T.31 8.3.5 requires the DCE to respond CONNECT or result OK within
     * five seconds or it must result ERROR.  T.30 requires the data of
     * the HDLC frame to be tranmsitted in 3 s +/- 15%.  Thus, our
     * timeouts here must be at least 7500 ms and no more than 8500 ms.
     */
    bool frameSent;
    if (useV34) frameSent = true;
    else {
	if (!atCmd(conf.class1SwitchingCmd, AT_OK)) {
	    protoTrace("Failure to receive silence.");
	    return (false);
	}
	frameSent = (atCmd(thCmd, AT_NOTHING) && atResponse(rbuf, 7550) == AT_CONNECT);
    }
    if (!frameSent)
	return (false);
    if (pwd != fxStr::null) {
	startTimeout(7550);
	bool frameSent = sendFrame(FCF_PWD|FCF_SNDR, pwd, false);
	stopTimeout("sending PWD frame");
	if (!frameSent)
	    return (false);
    }
    if (sub != fxStr::null) {
	startTimeout(7550);
	bool frameSent = sendFrame(FCF_SUB|FCF_SNDR, sub, false);
	stopTimeout("sending SUB frame");
	if (!frameSent)
	    return (false);
    }
    startTimeout(7550);
    frameSent = sendFrame(FCF_TSI|FCF_SNDR, tsi, false);
    stopTimeout("sending TSI frame");
    if (!frameSent)
	return (false);
    startTimeout(7550);
    frameSent = sendFrame(FCF_DCS|FCF_SNDR, dcs_caps);
    stopTimeout("sending DCS frame");
    return (frameSent);
}

/*
 * Return whether or not the previously received DIS indicates
 * the remote side is capable of the T.30 DCS signalling rate.
 */
bool
Class1Modem::isCapable(u_int sr, FaxParams& dis)
{
    switch (sr) {
    case DCSSIGRATE_2400V27:
        if (!dis.isBitEnabled(FaxParams::BITNUM_SIGRATE_11) &&
            !dis.isBitEnabled(FaxParams::BITNUM_SIGRATE_12) &&
            !dis.isBitEnabled(FaxParams::BITNUM_SIGRATE_13) &&
            !dis.isBitEnabled(FaxParams::BITNUM_SIGRATE_14))
	    return (true);
	/* fall thru... */
    case DCSSIGRATE_4800V27:
	return dis.isBitEnabled(FaxParams::BITNUM_SIGRATE_12);
    case DCSSIGRATE_9600V29:
    case DCSSIGRATE_7200V29:
	return dis.isBitEnabled(FaxParams::BITNUM_SIGRATE_11);
    case DCSSIGRATE_14400V33:
    case DCSSIGRATE_12000V33:
	// post-1994 revisions of T.30 indicate that V.33 should
	// only be used when it is specifically permitted by DIS
	return(dis.isBitEnabled(FaxParams::BITNUM_SIGRATE_11) &&
	    dis.isBitEnabled(FaxParams::BITNUM_SIGRATE_12) &&
	    dis.isBitEnabled(FaxParams::BITNUM_SIGRATE_13) &&
	    !dis.isBitEnabled(FaxParams::BITNUM_SIGRATE_14));
    case DCSSIGRATE_14400V17:
    case DCSSIGRATE_12000V17:
    case DCSSIGRATE_9600V17:
    case DCSSIGRATE_7200V17:
	return(dis.isBitEnabled(FaxParams::BITNUM_SIGRATE_11) &&
	    dis.isBitEnabled(FaxParams::BITNUM_SIGRATE_12) &&
	    !dis.isBitEnabled(FaxParams::BITNUM_SIGRATE_13) &&
	    dis.isBitEnabled(FaxParams::BITNUM_SIGRATE_14));
    }
    return (false);
}

/*
 * Send capabilities and do training.
 */
bool
Class1Modem::sendTraining(Class2Params& params, int tries, fxStr& emsg)
{
    u_short attempt = 0;
    if (tries == 0) {
	emsg = "DIS/DTC received 3 times; DCS not recognized";
	protoTrace(emsg);
	if (useV34) hadV34Trouble = true;	// sadly, some receivers will do this with V.34
	return (false);
    }
    params.update(false);
    // we should respect the frame-size preference indication by the remote (DIS_FRAMESIZE)
    if (params.ec != EC_DISABLE && 
	(conf.class1ECMFrameSize == 64 || dis_caps.isBitEnabled(FaxParams::BITNUM_FRAMESIZE_DIS))) {
	params.setBit(FaxParams::BITNUM_FRAMESIZE_DCS, true); // we don't want to add this bit if not using ECM
	frameSize = 64;
    } else
	frameSize = 256;

    if (!useV34) {
	/*
	 * Select Class 1 capability: use params.br to hunt
	 * for the best signalling scheme acceptable to both
	 * local and remote (based on received DIS and modem
	 * capabilities gleaned at modem setup time).
	 */
	if (!curcap)
	    curcap = findBRCapability(params.br, xmitCaps);
	curcap++;
	/*
	 * We assume that if the sender requested 9600 or 7200 baud
	 * and if the modem supports both V.17 and V.29 that the
	 * desired modulation is V.29.
	 */
	do {
	    if (!dropToNextBR(params))
		goto failed;
	} while ((params.br == BR_9600 || params.br == BR_7200) && curcap->mod != V29);
    }
    do {
	attempt++;
	if (!useV34) {
	    /*
	     * Override the Class 2 parameter bit rate
	     * capability and use the signalling rate
	     * calculated from the modem's capabilities
	     * and the received DIS.  This is because
	     * the Class 2 state does not include the
	     * modulation technique (v.27, v.29, v.17, v.33).
	     *
	     * Technically, according to post-1994 revisions
	     * of T.30, V.33 should not be used except
	     * in the case where the remote announces
	     * specific V.33 support with the 1,1,1,0 rate
	     * bits set.  However, for the sake of versatility
	     * we'll not enforce this upon modems that support
	     * V.33 but not V.17 and will require the user
	     * to disable V.33 if it becomes problematic.  For
	     * modems that support both V.17 and V.33 the
	     * latter is never used.
	     */
	    params.br = curcap->br;
	    params.setBit(FaxParams::BITNUM_SIGRATE_11, curcap->sr&DCSSIGRATE_9600V29);
	    params.setBit(FaxParams::BITNUM_SIGRATE_12, curcap->sr&DCSSIGRATE_4800V27);
	    params.setBit(FaxParams::BITNUM_SIGRATE_13, curcap->sr&DCSSIGRATE_14400V33);
	    params.setBit(FaxParams::BITNUM_SIGRATE_14, curcap->sr&DCSSIGRATE_14400V17);
	    /*
	     * Set the number of train attemps on the same
	     * modulation; having set it to 1 we immediately drop
	     * the speed if the training has been failed.
	     * This parameter is not specified by T.30
	     * (the algorith left implementation defined),
	     * so we choose the exact value according to our
	     * common sense.
	     */
	} else {
	    /*
	     * T.30 Table 2 Note 33 says that when V.34-fax is used
	     * DCS bits 11-14 should be set to zero.
	     */
	    params.setBit(FaxParams::BITNUM_SIGRATE_11, false);
	    params.setBit(FaxParams::BITNUM_SIGRATE_12, false);
	    params.setBit(FaxParams::BITNUM_SIGRATE_13, false);
	    params.setBit(FaxParams::BITNUM_SIGRATE_14, false);
	}
	int t = 1;
	do {
	    if (!useV34) protoTrace("SEND training at %s %s",
		modulationNames[curcap->mod],
		Class2Params::bitRateNames[curcap->br]);
	    if (!sendPrologue(params, lid)) {
		if (abortRequested())
		    goto done;
		protoTrace("Error sending T.30 prologue frames");
		continue;
	    }

	    /*
	     * V.8 handshaking provides training for V.34-fax connections
	     */
	    if (!useV34) {
		/*
		 * Delay before switching to high speed carrier
		 * to send the TCF data as required by T.30 chapter
		 * 5 note 3.
		 *
		 * Historically this delay was enforced by a pause,
		 * however, +FTS must be used.  See the notes preceding
		 * Class1PPMWaitCmd above.
		 */
		if (!atCmd(conf.class1TCFWaitCmd, AT_OK)) {
		    emsg = "Stop and wait failure (modem on hook)";
		    protoTrace(emsg);
		    return (send_retry);
		}

		if (!sendTCF(params, TCF_DURATION)) {
		    if (abortRequested())
			goto done;
		    protoTrace("Problem sending TCF data");
		}

		/*
		 * Some modems may respond OK following TCF transmission
		 * so quickly that the carrier signal has not actually 
		 * dropped.  T.30 requires the receiver to wait 75 +/- 20 
		 * ms before sending a response.  Here we explicitly look for 
		 * that silence before looking for the low-speed carrier.  
		 * Doing this resolves "DIS/DTC received 3 times" errors 
		 * between USR modems and certain HP OfficeJets, in 
		 * particular.
        	 */
		if (conf.class1ResponseWaitCmd != "") {
		    atCmd(conf.class1ResponseWaitCmd, AT_OK);
		}
	    }

	    /*
	     * Receive response to training.  Acceptable
	     * responses are: DIS or DTC (DTC not handled),
	     * FTT, or CFR; and also a premature DCN.
	     */
	    HDLCFrame frame(conf.class1FrameOverhead);
	    if (recvFrame(frame, FCF_SNDR, conf.t4Timer)) {
		do {
		    switch (frame.getFCF()) {
		    case FCF_NSF:
			recvNSF(NSF(frame.getFrameData(), frame.getFrameDataLength()-1, frameRev));
			break;
		    case FCF_CSI:
			{ fxStr csi; recvCSI(decodeTSI(csi, frame)); }
			break;
		    }
		} while (frame.moreFrames() && recvFrame(frame, FCF_SNDR, conf.t2Timer));
	    } 
	    if (frame.isOK()) {
		switch (frame.getFCF()) {
		case FCF_CFR:		// training confirmed
		    if (!useV34) protoTrace("TRAINING succeeded");
		    setDataTimeout(60, params.br);
		    return (true);
		case FCF_CRP:		// command repeat
		case FCF_FTT:		// failure to train, retry
		    break;
		case FCF_DIS:		// new capabilities, maybe
		    { FaxParams newDIS = frame.getDIS();
		      if (newDIS != dis_caps) {
			/*
			dis_caps = newDIS;
			params.setFromDIS(dis_caps);
			 *
			 * The above code was commented because to
			 * use the newDIS we need to do more work like
			 *     sendClientCapabilitiesOK()
			 *     sendSetupParams()
			 * So we ignore newDIS.
			 * It will work if old dis 'less' then newDIS.
			 */
			curcap = NULL;
			if (useV34 && params.ec == EC_DISABLE) {
			    protoTrace("V.34-Fax session, but DIS signal contains no ECM bit; ECM forced.");
			    params.ec = EC_ENABLE256;
			}
		      }
		    }
		    return (sendTraining(params, --tries, emsg));
		default:
		    if (frame.getFCF() == FCF_DCN) {
			/*
			 * The receiver is disconnecting.  This can happen
			 * if the receiver is exhaused from retraining, but
			 * it also happens in situations where, for example,
			 * the receiver determines that there is a modulator
			 * incompatibility (i.e. with V.17).  In that case,
			 * we must prevent ourselves from redialing and
			 * reattempting V.17 training, or we'll never get
			 * through.
			 */
			if (curcap->mod == V17 && attempt == 1 && tries == 3) hadV17Trouble = true;
			emsg = "RSRPEC error/got DCN";
		    } else
			emsg = "RSPREC invalid response received";
		    goto done;
		}
	    } else {
		// delay to give other side time to reset
		pause(conf.class1TrainingRecovery);
	    }
	} while (--t > 0);
	/*
	 * (t) attempts at the current speed failed, drop
	 * the signalling rate to the next lower rate supported
	 * by the local & remote sides and try again.
	 */
    } while (!useV34 && dropToNextBR(params));
failed:
    emsg = "Failure to train remote modem at 2400 bps or minimum speed";
done:
    if (!useV34) protoTrace("TRAINING failed");
    return (false);
}

/*
 * Select the next lower signalling rate that's
 * acceptable to both local and remote machines.
 */
bool
Class1Modem::dropToNextBR(Class2Params& params)
{
    if (curcap->br == BR_2400)
	return (false);
    const Class1Cap* oldcap = curcap;
    curcap--;
    for (;;) {
	if (curcap) {
	    /*
	     * Hunt for compatibility with remote at this baud rate.
	     * We don't drop from V.29 to V.17 because if the 
	     * receiver supports V.17 then we probably tried
	     * it already without success.
	     */
	    while (curcap->br == params.br) {
		if (isCapable(curcap->sr, dis_caps) && !(oldcap->mod == V29 && curcap->mod == V17))
		    return (true);
		curcap--;
	    }
	}
	if (params.br == minsp)
	    return (false);
	params.br--;
	// get ``best capability'' of modem at this baud rate
	curcap = findBRCapability(params.br, xmitCaps);
    }
    /*NOTREACHED*/
}

/*
 * Select the next higher signalling rate that's
 * acceptable to both local and remote machines.
 */
bool
Class1Modem::raiseToNextBR(Class2Params& params)
{
    for (;;) {
	if (params.br == BR_14400)	// highest speed
	    return (false);
	// get ``best capability'' of modem at this baud rate
	curcap = findBRCapability(++params.br, xmitCaps);
	if (curcap) {
	    // hunt for compatibility with remote at this baud rate
	    do {
		if (isCapable(curcap->sr, dis_caps))
		    return (true);
		curcap--;
	    } while (curcap->br == params.br);
	}
    }
    /*NOTREACHED*/
}

void
Class1Modem::blockData(u_int byte, bool flag)
{
    if (useV34) {
	// With V.34-fax the DTE makes the stuffing
	byte =  (((byte>>0)&1)<<7)|(((byte>>1)&1)<<6)|
		(((byte>>2)&1)<<5)|(((byte>>3)&1)<<4)|
		(((byte>>4)&1)<<3)|(((byte>>5)&1)<<2)|
		(((byte>>6)&1)<<1)|(((byte>>7)&1)<<0);
	ecmStuffedBlock[ecmStuffedBlockPos++] = byte;
	return;
    }
    for (u_int j = 8; j > 0; j--) {
	u_short bit = (byte & (1 << (j - 1))) != 0 ? 1 : 0;
	ecmByte |= (bit << ecmBitPos);
	ecmBitPos++;
	if (ecmBitPos == 8) {
	    ecmStuffedBlock[ecmStuffedBlockPos++] = ecmByte;
	    ecmBitPos = 0;
	    ecmByte = 0;
	}
	// add transparent zero bits if needed
	if (bit == 1 && !flag) ecmOnes++;
	else ecmOnes = 0;
	if (ecmOnes == 5) {
	    ecmBitPos++;
	    if (ecmBitPos == 8) {
		ecmStuffedBlock[ecmStuffedBlockPos++] = ecmByte;
		ecmBitPos = 0;
		ecmByte = 0;
	    }
	    ecmOnes = 0;
	}
    }
}

/*
 * Buffer ECM HDLC image frames until a full block is received.
 * Perform T.30-A image block transmission protocol.
 */
bool
Class1Modem::blockFrame(const u_char* bitrev, bool lastframe, u_int ppmcmd, fxStr& emsg)
{
    // we have a full image frame

    for (u_int i = 0; i < ecmFramePos; i++)
	ecmBlock[ecmBlockPos++] = ecmFrame[i];
    ecmFramePos = 0;
    if (frameNumber == 256 || lastframe) {
	fxAssert(frameNumber <= 256, "Invalid frameNumber value.");
	ecmBlockPos = 0;
	bool lastblock = lastframe;

	// We now have a full image block without stuffed zero bits.
	// As the remote can request any frame of the block until
	// MCF we must keep the full image block available.

	bool blockgood = false, renegotiate = false, constrain = false;
	u_short pprcnt = 0;
	char ppr[32];				// 256 bits
	for (u_int i = 0; i < 32; i++) ppr[i] = 0xff;
	u_short badframes = frameNumber, badframesbefore = 0;
	bool dolongtrain = false;

	do {
	    u_short fcount = 0;
	    u_short fcountuniq = 0;
	    ecmStuffedBlockPos = 0;

	    if (!useV34) {
		// synchronize with 200 ms of 0x7e flags
		for (u_int i = 0; i < params.transferSize(200); i++)
		    blockData(0x7e, true);
	    }

	    u_char* firstframe = (u_char*) malloc(frameSize + 6);
	    fxAssert(firstframe != NULL, "ECM procedure error (frame duplication).");
	    firstframe[0] = 0x1;			// marked as unused
	    for (u_short fnum = 0; fnum < frameNumber; fnum++) {
		u_int pprpos, pprval;
        	for (pprpos = 0, pprval = fnum; pprval >= 8; pprval -= 8) pprpos++;
        	if (ppr[pprpos] & frameRev[1 << pprval]) {
		    HDLCFrame ecmframe(5);
		    // frame bit marked for transmission
		    fcount++;
		    for (u_int i = fnum * (frameSize + 4);
			i < (fnum + 1) * (frameSize + 4); i++) {
			ecmframe.put(ecmBlock[i]);
			blockData(ecmBlock[i], false);
		    }
		    int fcs1 = ecmframe.getCRC() >> 8;		// 1st byte FCS
		    int fcs2 = ecmframe.getCRC() & 0xff;	// 2nd byte FCS
		    ecmframe.put(fcs1); ecmframe.put(fcs2);
		    blockData(fcs1, false);
		    blockData(fcs2, false);
		    traceHDLCFrame("<--", ecmframe, true);
		    protoTrace("SEND send frame number %u", fnum);

		    if (!useV34) {
			// separate frames with a 0x7e flag
			blockData(0x7e, true);
		    }

		    if (firstframe[0] == 0x1) {
			for (u_int i = 0; i < (frameSize + 6); i++) {
			    firstframe[i] = ecmframe[i];
			}
		    }
		}
	    }
	    fcountuniq = fcount;
	    if (fcount == 1 && pprcnt > 0) {
		// Some receivers may have a hard time hearing the first frame
		// so we repeat it.
		HDLCFrame ecmframe(5);
		fcount++;
		for (u_int i = 0; i < (frameSize + 6); i++) {
		    blockData(firstframe[i], false);
		}
		ecmframe.put(firstframe, (frameSize + 6));
		traceHDLCFrame("<--", ecmframe, true);
		protoTrace("SEND send frame number %u", frameRev[firstframe[3]]);
		if (!useV34) blockData(0x7e, true);
	    }
	    free(firstframe);
	    HDLCFrame rcpframe(5);
	    rcpframe.put(0xff); rcpframe.put(0xc0); rcpframe.put(0x61); rcpframe.put(0x96); rcpframe.put(0xd3);
	    for (u_short k = 0; k < 3; k++) {		// three RCP frames
		for (u_short j = 0; j < 5; j++)
		    blockData(rcpframe[j], false);
		traceHDLCFrame("<--", rcpframe, true);

		// separate frames with a 0x7e flag
		if (!useV34) blockData(0x7e, true);
	    }
	    // add one more flag to ensure one full flag gets transmitted before DLE+ETX
	    if (!useV34) blockData(0x7e, true);

	    // start up the high-speed carrier...
	    if (flowControl == FLOW_XONXOFF)   
		setXONXOFF(FLOW_XONXOFF, FLOW_NONE, ACT_FLUSH);
	    if (!useV34) {
		pause(conf.class1SendMsgDelay);		// T.30 5.3.2.4
		/*
		 * T.30 Section 5, Note 5 states that we must use long training
		 * on the first high-speed data message following CTC.
		 */
		fxStr tmCmd;
		if (dolongtrain) tmCmd = fxStr(curcap->value, tmCmdFmt);
		else tmCmd = fxStr(curcap[HasShortTraining(curcap)].value, tmCmdFmt);
		if (!atCmd(tmCmd, AT_CONNECT))
		    return (false);
		pause(conf.class1TMConnectDelay);
	    }
	    dolongtrain = false;

	    // The block is assembled.  Transmit it, adding transparent DLEs.  End with DLE+ETX.
	    u_char buf[2];
	    if (useV34) {
		// switch to primary channel
		buf[0] = DLE; buf[1] = 0x6B;	// <DLE><pri>
		if (!putModemData(buf, 2)) return (false);
		// wait for the ready indicator, <DLE><pri><DLE><prate>
		if (!waitForDCEChannel(false)) return (false);
		if (renegotiate) {
		    // Although spec says this can be done any time,
		    // in practice it must be done at this moment.
		    renegotiatePrimary(constrain);
		    renegotiate = false;
		    constrain = false;
		}
	    }
	    if (useV34) {
		// we intentionally do not send the FCS bytes as the DCE regenerates them
		// send fcount frames separated by <DLE><ETX>
		buf[0] = DLE; buf[1] = ETX;
		u_short v34frame;
		for (v34frame = 0; v34frame < fcount; v34frame++) {
		    if (!putModemDLEData(ecmStuffedBlock, frameSize + 4, bitrev, getDataTimeout()))
			return (false);
		    if (!putModemData(buf, 2)) return (false);
		    ecmStuffedBlock += (frameSize + 6);
		}
		// send 3 RCP frames separated by <DLE><ETX>
		for (v34frame = 0; v34frame < 3; v34frame++) {
		    if (!putModemDLEData(ecmStuffedBlock, 3, bitrev, getDataTimeout()))
			return (false);
		    if (!putModemData(buf, 2)) return (false);
		    ecmStuffedBlock += 5;
		}
		ecmStuffedBlock -= ecmStuffedBlockPos;
	    } else {
		if (!putModemDLEData(ecmStuffedBlock, ecmStuffedBlockPos, bitrev, getDataTimeout()))
		    return (false);
	    }
	    if (useV34) {
		// switch to control channel
		buf[0] = DLE; buf[1] = 0x6D;	// <DLE><ctrl>
		if (!putModemData(buf, 2)) return (false);
		// wait for the ready indicator, <DLE><ctrl><DLE><crate>
		if (!waitForDCEChannel(true)) {
		    emsg = "Failed to properly open control V.34 channel.";
		    protoTrace(emsg);
		    return (false);
		}
	    } else {
		buf[0] = DLE; buf[1] = ETX;
		if (!putModemData(buf, 2)) return (false);

		// Wait for transmit buffer to empty.
		ATResponse r;
		while ((r = atResponse(rbuf, getDataTimeout())) == AT_OTHER);
        	if (!(r == AT_OK)) {
		    return (false);
		}
	    }

	    if (flowControl == FLOW_XONXOFF)
		setXONXOFF(FLOW_NONE, FLOW_NONE, ACT_DRAIN);

	    if (!useV34 && !atCmd(ppmcmd == FCF_MPS ? conf.class1PPMWaitCmd : conf.class1EOPWaitCmd, AT_OK)) {
		emsg = "Stop and wait failure (modem on hook)";
		protoTrace(emsg);
		return (false);
	    }

	    /*
	     * A pause here helps prevent getting RNR from some receivers.
	     * In theory (per spec) it should not be longer than the smallest T2.
	     * In practice it cannot be shorter than the smallest T4.
	     *
	     * It is now disabled because our RNR/RR handling now functions and
	     * pausing 3 seconds needlessly slows down the process quite a bit.
	     */
	    //pause (3000);

	    /*
	     * Build PPS frame and send it.  We don't use I3 = 0xFF when sending
	     * zero-count frames because some receivers will read it as 256.
	     * Instead we send I3 = 0x00, which technically indicates one frame,
	     * but it should be harmless since any interpretation of I3 will not
	     * exceed previous indications, and the receiver has already acknowledged
	     * all frames properly received.  I3 indicates the *unique* frame count.
	     */
	    char pps[4];
	    if (!lastblock)
		pps[0] = 0x00;
	    else
		pps[0] = ppmcmd | 0x80;
	    pps[1] = frameRev[FaxModem::getPageNumberOfCall() - 1];
	    pps[2] = frameRev[blockNumber];
	    pps[3] = frameRev[(fcountuniq == 0 ? 0 : (fcountuniq - 1))];
	    u_short ppscnt = 0, crpcnt = 0;
	    bool gotppr = false;
	    /* get MCF/PPR/RNR */
	    HDLCFrame pprframe(conf.class1FrameOverhead);
	    do {
		if (!useV34 && !atCmd(thCmd, AT_CONNECT))
		    break;
		startTimeout(3000);
		sendFrame(FCF_PPS|FCF_SNDR, fxStr(pps, 4));
		stopTimeout("sending PPS frame");
		tracePPM("SEND send", FCF_PPS);
		tracePPM("SEND send", pps[0]);

		// Some receivers will almost always miss our first PPS message, and
		// in those cases waiting T2 for a response will cause the remote to
		// hang up.  So, using T4 here is imperative so that our second PPS
		// message happens before the remote decides to hang up. As we're in
		// a "RESPONSE REC" operation, anyway, this is correct behavior.
		if (gotppr = recvFrame(pprframe, FCF_SNDR, conf.t4Timer)) {
		    tracePPR("SEND recv", pprframe.getFCF());
		    if (pprframe.getFCF() == FCF_CRP) {
			gotppr = false;
			crpcnt++;
			ppscnt = 0;
			if (!useV34 && !atCmd(conf.class1SwitchingCmd, AT_OK)) {
			    emsg = "Failure to receive silence.";
			    protoTrace(emsg);
			    return (false);
			}
		    }
		}
	    } while (!gotppr && (++ppscnt < 3) && (crpcnt < 3) && !(useV34 && gotEOT));
	    if (gotppr) {
		if (!useV34 && !atCmd(conf.class1SwitchingCmd, AT_OK)) {
		    emsg = "Failure to receive silence.";
		    protoTrace(emsg);
		    return (false);
		}
		if (pprframe.getFCF() == FCF_RNR) {
		    u_int t1 = howmany(conf.t1Timer, 1000);
		    time_t start = Sys::now();
		    gotppr = false;
		    do {
			if ((unsigned) Sys::now()-start >= t1) {
			    // we use T1 rather than T5 to "minimize transmission inefficiency" (T.30 A.5.4.1)
			    emsg = "Receiver flow control exceeded timer.";
			    if (ppmcmd == FCF_EOM) batchingError = true;
			    protoTrace(emsg);
			    return (false);
			}
			u_short rrcnt = 0, crpcnt = 0;
			bool gotmsg = false;
			do {
			    if (!useV34 && !atCmd(thCmd, AT_CONNECT))
				break;
			    startTimeout(3000);
			    sendFrame(FCF_RR|FCF_SNDR);
			    stopTimeout("sending RR frame");
			    tracePPM("SEND send", FCF_RR);
			    // T.30 states that we must wait no more than T4 between unanswered RR signals.
			    if (gotmsg = recvFrame(pprframe, FCF_SNDR, conf.t4Timer)) {
				tracePPR("SEND recv", pprframe.getFCF());
				if (pprframe.getFCF() == FCF_CRP) {
				    gotmsg = false;
				    crpcnt++;
				    rrcnt = 0;
				    if (!useV34 && !atCmd(conf.class1SwitchingCmd, AT_OK)) {
					emsg = "Failure to receive silence.";
					protoTrace(emsg);
					return (false);
				    }
				}
			    }
			} while (!gotmsg && (++rrcnt < 3) && (crpcnt < 3));
			if (!gotmsg) {
			    emsg = "No response to RR repeated 3 times.";
			    protoTrace(emsg);
			    return (false);
			}
			switch (pprframe.getFCF()) {
			    case FCF_PPR:
			    case FCF_MCF:
				gotppr = true;
				break;
			    case FCF_RNR:
				if (!useV34 && !atCmd(conf.class1SwitchingCmd, AT_OK)) {
				    emsg = "Failure to receive silence.";
				    protoTrace(emsg);
				    return (false);
				}
				break;
			    default:
				emsg = "COMREC invalid response received to RR.";
				protoTrace(emsg);
				return (false);
				break;
			}
		    } while (!gotppr);		
		}
		bool doctceor;
		switch (pprframe.getFCF()) {
		    case FCF_MCF:
		    case FCF_PIP:
			hadV34Trouble = false;
			blockgood = true;
			signalRcvd = pprframe.getFCF();
			break;
		    case FCF_PPR:
			{
			    pprcnt++;
			    // update ppr
			    for (u_int i = 3; i < (pprframe.getLength() - (conf.class1FrameOverhead - 2)); i++) {
				ppr[i-3] = pprframe[i];
			    }
			    badframesbefore = badframes;
			    badframes = 0;
			    for (u_int j = 0; j < frameNumber; j++) {
				u_int pprpos, pprval;
				for (pprpos = 0, pprval = j; pprval >= 8; pprval -= 8) pprpos++;
				if (ppr[pprpos] & frameRev[1 << pprval]) {
				    badframes++;
				}
			    }
			}
			doctceor = (pprcnt == 4);
			/*
			 * T.30 Annex F prohibits CTC in V.34-Fax.  Per the spec our options
			 * are to do EOR or DCN.  However, many receivers will allow us to
			 * simply continue sending image blocks followed by PPS.  Coupled with
			 * primary rate negotiations, this becomes a better-than-CTC solution.
			 * Do this up to 12 attempts and only when something has gotten through.
			 */
			if (useV34) {
			    if (pprcnt >= 4 && badframes) hadV34Trouble = true;	// problematic V.34?
			    if (pprcnt == 8) doctceor = true;
			    if (conf.class1PersistentECM && badframes && badframes != frameNumber) doctceor = false;
			    if (pprcnt == 12) doctceor = true;
			    if (!doctceor && badframes && badframes >= (badframesbefore / 2)) {
				/*
				 * Request to renegotiate the primary rate.  (T.31-A1 B.8.5)
				 * In practice, if we do not constrain the rate then
				 * we may likely speed up the rate; so we constrain it.
				 */
				renegotiate = true;
				constrain = true;
			    }
			}
			if (doctceor) {
			    pprcnt = 0;
			    // Some receivers will ignorantly transmit PPR showing all frames good,
			    // so if that's the case then do EOR instead of CTC.
			    if (badframes == 0) {
				hadV34Trouble = false;
				blockgood = true;
				signalRcvd = FCF_MCF;
			    }
			    if (!useV34 && curcap->mod == V17 && badframes == frameNumber) {
				// looks like a V.17 modulator incompatibility that managed to pass TCF
				// we set hasV17Trouble to help future calls to this destination
				protoTrace("The destination appears to have trouble with V.17.");
				hadV17Trouble = true;
			    }
			    // There is no CTC with V.34-fax (T.30 Annex F.3.4.5 Note 1).
			    if (conf.class1PersistentECM && !useV34 && (blockgood == false) && 
				!((curcap->br == 0) && (badframes >= badframesbefore))) {
				// send ctc even at 2400 baud if we're getting somewhere
				if (curcap->br != 0) {
				    u_char oldmod = curcap->mod;
				    do {
					if (!dropToNextBR(params)) {
					    // We have a minimum speed that's not BR_2400,
					    // and we're there now.  Undo curcap change...
					    curcap++;
					}
					// drop to the next modulation protocol if we're not getting anywhere
				    } while (curcap->br != 0 && badframes >= badframesbefore && curcap->mod == oldmod);
				}
				char ctc[2];
				ctc[0] = 0;
				ctc[1] = curcap->sr >> 8;
				bool gotctr = false;
				u_short ctccnt = 0, crpcnt = 0;
				HDLCFrame ctrframe(conf.class1FrameOverhead);
				do {
				    if (!atCmd(thCmd, AT_CONNECT))
					break;
				    startTimeout(3000);
				    sendFrame(FCF_CTC|FCF_SNDR, fxStr(ctc, 2));
				    stopTimeout("sending CTC frame");
				    tracePPM("SEND send", FCF_CTC);
				    if (gotctr = recvFrame(ctrframe, FCF_SNDR, conf.t4Timer)) {
					tracePPR("SEND recv", ctrframe.getFCF());
					if (ctrframe.getFCF() == FCF_CRP) {
					    gotctr = false;
					    crpcnt++;
					    ctccnt = 0;
					    if (!atCmd(conf.class1SwitchingCmd, AT_OK)) {
						emsg = "Failure to receive silence.";
						protoTrace(emsg);
						return (false);
					    }
					}
				    }
				} while (!gotctr && (++ctccnt < 3) && (crpcnt < 3));
				if (!gotctr) {
				    emsg = "No response to CTC repeated 3 times.";
				    protoTrace(emsg);
				    return (false);
				}
				if (!ctrframe.getFCF() == FCF_CTR) {
				    emsg = "COMREC invalid response received to CTC.";
				    protoTrace(emsg);
				    return (false);
				}
				dolongtrain = true;	// T.30 states that we must use long-training next
			    } else {
				/*
				 * At this point data corruption is inevitable if all data
				 * frames have not been received correctly.  This is tolerable
				 * with MH and MR data, as the effect of the corruption
				 * will be limited, but with MMR data all data following the
				 * corrupt frame will be meaningless: the page image will be
				 * truncated on the receiver's end.  So if this is the case
				 * we disconnect, and hopefully we try again successfully.  If
				 * this happens repeatedly to the same destination, then
				 * disabling MMR to this destination would be advisable.
				 */
				if (blockgood == false && params.df == DF_2DMMR) {
				    emsg = "Failure to transmit clean MMR image data.";
				    protoTrace(emsg);
				    return (false);
				}
				bool goterr = false;
				u_short eorcnt = 0, crpcnt = 0;
				HDLCFrame errframe(conf.class1FrameOverhead);
				do {
				    if (!useV34 && !atCmd(thCmd, AT_CONNECT))
					break;
				    startTimeout(3000);
				    sendFrame(FCF_EOR|FCF_SNDR, fxStr(pps, 1));
				    stopTimeout("sending EOR frame");
				    tracePPM("SEND send", FCF_EOR);
				    tracePPM("SEND send", pps[0]);
				    if (goterr = recvFrame(errframe, FCF_SNDR, conf.t4Timer)) {
					tracePPR("SEND recv", errframe.getFCF());
					if (errframe.getFCF() == FCF_CRP) {
					    goterr = false;
					    crpcnt++;
					    eorcnt = 0;
					    if (!useV34 && !atCmd(conf.class1SwitchingCmd, AT_OK)) {
						emsg = "Failure to receive silence.";
						protoTrace(emsg);
						return (false);
					    }
					}
				    }
				} while (!goterr && (++eorcnt < 3) && (crpcnt < 3));
				if (!goterr) {
				    emsg = "No response to EOR repeated 3 times.";
				    if (ppmcmd == FCF_EOM) batchingError = true;
				    protoTrace(emsg);
				    return (false);
				}
				if (errframe.getFCF() == FCF_RNR) {
				    u_int t1 = howmany(conf.t1Timer, 1000);
				    time_t start = Sys::now();
				    goterr = false;
				    do {
					if ((unsigned) Sys::now()-start >= t1) {
					    // we use T1 rather than T5 to "minimize transmission inefficiency" (T.30 A.5.4.1)
					    emsg = "Receiver flow control exceeded timer.";
					    if (ppmcmd == FCF_EOM) batchingError = true;
					    protoTrace(emsg);
					    return (false);
					}
					u_short rrcnt = 0, crpcnt = 0;
					bool gotmsg = false;
					do {
					    if (!useV34 && !atCmd(thCmd, AT_CONNECT))
						break;
					    startTimeout(3000);
					    sendFrame(FCF_RR|FCF_SNDR);
					    stopTimeout("sending RR frame");
					    tracePPM("SEND send", FCF_RR);
					    // T.30 states that we must wait no more than T4 between unanswered RR signals.
					    if (gotmsg = recvFrame(errframe, FCF_SNDR, conf.t4Timer)) {
						tracePPR("SEND recv", errframe.getFCF());
						if (errframe.getFCF() == FCF_CRP) {
						    gotmsg = false;
						    crpcnt++;
						    rrcnt = 0;
						    if (!useV34 && !atCmd(conf.class1SwitchingCmd, AT_OK)) {
							emsg = "Failure to receive silence.";
							protoTrace(emsg);
							return (false);
						    }
						}
					    }
					} while (!gotmsg && (++rrcnt < 3) && (crpcnt < 3));
					if (!gotmsg) {
					    emsg = "No response to RR repeated 3 times.";
					    protoTrace(emsg);
					    return (false);
					}
					switch (errframe.getFCF()) {
					    case FCF_ERR:
						goterr = true;
						break;
					    case FCF_RNR:
						if (!useV34 && !atCmd(conf.class1SwitchingCmd, AT_OK)) {
						    emsg = "Failure to receive silence.";
						    protoTrace(emsg);
						    return (false);
						}
						break;
					    default:
						emsg = "COMREC invalid response received to RR.";
						protoTrace(emsg);
						return (false);
						break;
					}
				    } while (!goterr);		
				}
				if (!(errframe.getFCF() == FCF_ERR)) {
				    emsg = "COMREC invalid response received to EOR.";
				    protoTrace(emsg);
				    return (false);
				}
				blockgood = true;
				signalRcvd = FCF_MCF;
			    }
			}
			break;
		    default:
			emsg = "COMREC invalid response received to PPS.";
			protoTrace(emsg);
			return(false);
		}
	    } else {
		emsg = "No response to PPS repeated 3 times.";
		if (ppmcmd == FCF_EOM) batchingError = true;
		protoTrace(emsg);
		return (false);
	    }
	} while (!blockgood);
	frameNumber = 0;
	if (lastblock) blockNumber = 0;
	else blockNumber++;
    }
    return (true);
}

/*
 * Send T.30-A framed image data.
 */
bool
Class1Modem::sendClass1ECMData(const u_char* data, u_int cc, const u_char* bitrev, bool eod, u_int ppmcmd, fxStr& emsg)
{
    /*
     * Buffer data into the block.  We buffer the entire block
     * before sending it to prevent any modem buffer underruns.
     * Later we send it to putModemDLEData() which adds the 
     * transparent DLE characters and transmits it.
     */
    for (u_int i = 0; i < cc; i++) {
	if (ecmFramePos == 0) {
	    ecmFrame[ecmFramePos++] = 0xff; 	// address field
	    ecmFrame[ecmFramePos++] = 0xc0;	// control field
	    ecmFrame[ecmFramePos++] = 0x60;	// FCD FCF
	    ecmFrame[ecmFramePos++] = frameRev[frameNumber++];	// block frame number
	}
	ecmFrame[ecmFramePos++] = frameRev[data[i]];
	if (ecmFramePos == (frameSize + 4)) {
	    if (!blockFrame(bitrev, ((i == (cc - 1)) && eod), ppmcmd, emsg))
		return (false);
	}
    }
    if (eod) {
	if (ecmFramePos != 0)	{
	    // frame must be filled to end with zero-data
	    while (ecmFramePos < (frameSize + 4)) ecmFrame[ecmFramePos++] = 0x00;
	}
	if (!blockFrame(bitrev, true, ppmcmd, emsg))
	    return (false);
    }
    return (true);
}

/*
 * Send data for the current page.
 */
bool
Class1Modem::sendPageData(u_char* data, u_int cc, const u_char* bitrev, bool ecm, fxStr& emsg)
{
    beginTimedTransfer();
    bool rc;
    if (ecm)
	rc = sendClass1ECMData(data, cc, bitrev, false, 0, emsg);
    else {
	rc = sendClass1Data(data, cc, bitrev, false);
	protoTrace("SENT %u bytes of data", cc);
    }
    endTimedTransfer();
    return rc;
}

/*
 * Send RTC to terminate a page.  Note that we pad the
 * RTC with zero fill to "push it out on the wire".  It
 * seems that some Class 1 modems do not immediately
 * send all the data they are presented.
 */
bool
Class1Modem::sendRTC(Class2Params params, u_int ppmcmd, int lastbyte, uint32 rows, fxStr& emsg)
{
    if (params.df == DF_JBIG) {
	/*
	 * If we ever needed to send NEWLEN or other JBIG-terminating
	 * markers this is where we would do it.
	 */
	//u_char newlen[8] = { 0xFF, 0x05, 
	//    (rows>>24)&0xFF, (rows>>16)&0xFF, (rows>>8)&0xFF, rows&0xFF,
	//    0xFF, 0x02 };	// SDNORM is added per spec
	//return sendClass1ECMData(newlen, 8, rtcRev, true, ppmcmd, emsg);
	return sendClass1ECMData(NULL, 0, rtcRev, true, ppmcmd, emsg);
    }

    // determine the number of trailing zeros on the last byte of data
    u_short zeros = 0;
    for (short i = 7; i >= 0; i--) {
	if (lastbyte & (1<<i)) break;
	else zeros++;
    }
    /*
     * These are intentionally reverse-encoded in order to keep
     * rtcRev and bitrev in sendPage() in agreement.  They are also
     * end-padded with zeros to help "push" them out of the modem.
     * We explicitly set the zeros in the padding so as to prevent
     * the "unset" garbage values from confusing the receiver.
     * We don't send that padding with ECM, as it's unnecessary.
     */
    static const u_char RTC1D[9+20] =
	{ 0x00,0x08,0x80,0x00,0x08,0x80,0x00,0x08,0x80,
	  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
	  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00 };
    static const u_char RTC2D[10+20] =
	{ 0x00,0x18,0x00,0x03,0x60,0x00,0x0C,0x80,0x01,0x30,
	  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
	  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00 };
    // T.6 does not allow zero-fill until after EOFB and not before.
    u_char EOFB[3];
	EOFB[0] = (0x0800 >> zeros) & 0xFF;
	EOFB[1] = (0x8008 >> zeros) & 0xFF;
	EOFB[2] = 0x80 >> zeros;
    if (params.df == DF_2DMMR) {
	protoTrace("SEND EOFB");
	return sendClass1ECMData(EOFB, 3, rtcRev, true, ppmcmd, emsg);
    }
    if (params.is2D()) {
	protoTrace("SEND 2D RTC");
	if (params.ec != EC_DISABLE)
	    return sendClass1ECMData(RTC2D, 9, rtcRev, true, ppmcmd, emsg);
	else
	    return sendClass1Data(RTC2D, sizeof (RTC2D), rtcRev, true);
    } else {
	protoTrace("SEND 1D RTC");
	if (params.ec != EC_DISABLE)
	    return sendClass1ECMData(RTC1D, 10, rtcRev, true, ppmcmd, emsg);
	else
	    return sendClass1Data(RTC1D, sizeof (RTC1D), rtcRev, true);
    }
}

#define	EOLcheck(w,mask,code) \
    if ((w & mask) == code) { w |= mask; return (true); }

/*
 * Check the last 24 bits of received T.4-encoded
 * data (presumed to be in LSB2MSB bit order) for
 * an EOL code and, if one is found, foul the data
 * to insure future calls do not re-recognize an
 * EOL code.
 */
static bool
EOLcode(u_long& w)
{
    if ((w & 0x00f00f) == 0) {
	EOLcheck(w, 0x00f0ff, 0x000080);
	EOLcheck(w, 0x00f87f, 0x000040);
	EOLcheck(w, 0x00fc3f, 0x000020);
	EOLcheck(w, 0x00fe1f, 0x000010);
    }
    if ((w & 0x00ff00) == 0) {
	EOLcheck(w, 0x00ff0f, 0x000008);
	EOLcheck(w, 0x80ff07, 0x000004);
	EOLcheck(w, 0xc0ff03, 0x000002);
	EOLcheck(w, 0xe0ff01, 0x000001);
    }
    if ((w & 0xf00f00) == 0) {
	EOLcheck(w, 0xf0ff00, 0x008000);
	EOLcheck(w, 0xf87f00, 0x004000);
	EOLcheck(w, 0xfc3f00, 0x002000);
	EOLcheck(w, 0xfe1f00, 0x001000);
    }
    return (false);
}
#undef EOLcheck

/*
 * Send a page of data.
 */
bool
Class1Modem::sendPage(TIFF* tif, Class2Params& params, u_int pageChop, u_int ppmcmd, fxStr& emsg)
{
    int lastbyte = 0;
    if (params.ec == EC_DISABLE) {	// ECM does it later
	/*
	 * Set high speed carrier & start transfer.  If the
	 * negotiated modulation technique includes short
	 * training, then we use it here (it's used for all
	 * high speed carrier traffic other than the TCF).
	 */
	fxStr tmCmd(curcap[HasShortTraining(curcap)].value, tmCmdFmt);
	if (!atCmd(tmCmd, AT_CONNECT)) {
	    emsg = "Unable to establish message carrier";
	    protoTrace(emsg);
	    return (false);
	}
	// As with TCF, T.31 8.3.3 requires the DCE to report CONNECT at the beginning
	// of transmission of the training pattern rather than at the end.  We pause here
	// to allow the remote's +FRM to result in CONNECT.
	pause(conf.class1TMConnectDelay);
	if (flowControl == FLOW_XONXOFF)
	    setXONXOFF(FLOW_XONXOFF, FLOW_NONE, ACT_FLUSH);
    }

    bool rc = true;
    frameNumber = ecmBlockPos = ecmFramePos = ecmBitPos = ecmOnes = ecmByte = 0;
    protoTrace("SEND begin page");

    tstrip_t nstrips = TIFFNumberOfStrips(tif);
    uint32 rowsperstrip = 0;
    if (nstrips > 0) {

	/*
	 * RTFCC may mislead us here, so we temporarily
	 * adjust params.
	 */
	Class2Params newparams = params;
	uint16 compression;
	TIFFGetField(tif, TIFFTAG_COMPRESSION, &compression);
	if (compression != COMPRESSION_CCITTFAX4) {  
	    uint32 g3opts = 0;
	    TIFFGetField(tif, TIFFTAG_GROUP3OPTIONS, &g3opts);
	    if ((g3opts & GROUP3OPT_2DENCODING) == DF_2DMR)
		params.df = DF_2DMR;
	    else
		params.df = DF_1DMH;
	} else
	    params.df = DF_2DMMR;

	/*
	 * Correct bit order of data if not what modem expects.
	 */
	uint16 fillorder;
	TIFFGetFieldDefaulted(tif, TIFFTAG_FILLORDER, &fillorder);
	const u_char* bitrev =
	    TIFFGetBitRevTable(sendFillOrder != FILLORDER_LSB2MSB);
	/*
	 * Setup tag line processing.
	 */
	bool doTagLine = setupTagLineSlop(params);
	u_int ts = getTagLineSlop();
	/*
	 * Calculate total amount of space needed to read
	 * the image into memory (in its encoded format).
	 */
	uint32* stripbytecount;
	(void) TIFFGetField(tif, TIFFTAG_STRIPBYTECOUNTS, &stripbytecount);
	tstrip_t strip;
	u_long totdata = 0;
	for (strip = 0; strip < nstrips; strip++)
	    totdata += stripbytecount[strip];
	/*
	 * Read the image into memory.
	 */
	u_char* data = new u_char[totdata+ts];
	u_int off = ts;			// skip tag line slop area
	for (strip = 0; strip < nstrips; strip++) {
	    uint32 sbc = stripbytecount[strip];
	    if (sbc > 0 && TIFFReadRawStrip(tif, strip, data+off, sbc) >= 0)
		off += (u_int) sbc;
	}
	totdata -= pageChop;		// deduct trailing white space not sent
	TIFFGetFieldDefaulted(tif, TIFFTAG_ROWSPERSTRIP, &rowsperstrip);
	if (rowsperstrip == (uint32) -1)
	    TIFFGetField(tif, TIFFTAG_IMAGELENGTH, &rowsperstrip);

	/*
	 * Image the tag line, if intended.
	 */
	u_char* dp;
	if (doTagLine) {
	    u_long totbytes = totdata;
	    dp = imageTagLine(data+ts, fillorder, params, totbytes);
	    // Because the whole image is processed with MMR, 
	    // totdata is then determined during encoding.
	    totdata = (params.df == DF_2DMMR) ? totbytes : totdata+ts - (dp-data);
	} else
	    dp = data;

	/*
	 * After a page chop rowsperstrip is no longer valid, as the strip will
	 * be shorter.  Therefore, convertPhaseCData (for the benefit of JBIG) and 
	 * correctPhaseCData deliberately update rowsperstrip.
	 */

	if (conf.softRTFCC && params.df != newparams.df) {
	    switch (params.df) {
		case DF_1DMH:
		    protoTrace("Reading MH-compressed image file");
		    break;
		case DF_2DMR:
		    protoTrace("Reading MR-compressed image file");
		    break;
		case DF_2DMMR:
		    protoTrace("Reading MMR-compressed image file");
		    break;
	    }
	    dp = convertPhaseCData(dp, totdata, fillorder, params, newparams, rowsperstrip);
	}
	params = newparams;		// revert back

        /*
         * correct broken Phase C (T.4/T.6) data if neccessary 
         */
	if (params.df <= DF_2DMMR)
	    lastbyte = correctPhaseCData(dp, &totdata, fillorder, params, rowsperstrip);

	/*
	 * Send the page of data.  This is slightly complicated
	 * by the fact that we may have to add zero-fill before the
	 * EOL codes to bring the transmit time for each scanline
	 * up to the negotiated min-scanline time.
	 *
	 * Note that we blindly force the data to be in LSB2MSB bit
	 * order so that the EOL locating code works (if needed).
	 * This may result in two extraneous bit reversals if the
	 * modem wants the data in MSB2LSB order, but for now we'll
	 * avoid the temptation to optimize.
	 */
	if (params.df <= DF_2DMMR && fillorder != FILLORDER_LSB2MSB) {
	    TIFFReverseBits(dp, totdata);
	    lastbyte = frameRev[lastbyte];
	}
	u_int minLen = params.minScanlineSize();
	if (minLen > 0) {			// only in non-ECM
	    /*
	     * Client requires a non-zero min-scanline time.  We
	     * comply by zero-padding scanlines that have <minLen
	     * bytes of data to send.  To minimize underrun we
	     * do this padding in a strip-sized buffer.
	     */
	    u_char* fill = new u_char[minLen*rowsperstrip];
	    u_char* eoFill = fill + minLen*rowsperstrip;
	    u_char* fp = fill;

	    u_char* bp = dp;
	    u_char* ep = dp+totdata;
	    u_long w = 0xffffff;

            /*
             * Immediately copy leading EOL into the fill buffer,
             * because it has not to be padded. Note that leading
             * EOL is not byte-aligned, and so we also copy 4 bits
             * if image data. But that's OK, and may only lead to
             * adding one extra zero-fill byte to the first image
             * row.
             */
            *fp++ = *bp++;
            *fp++ = *bp++;
	    do {
		u_char* bol = bp;
                bool foundEOL;
		do {
		    w = (w<<8) | *bp++;
                    foundEOL = EOLcode(w);
                } while (!foundEOL && bp < ep);
		/*
                 * We're either after an EOL code or at the end of data.
		 * If necessary, insert zero-fill before the last byte
		 * in the EOL code so that we comply with the
		 * negotiated min-scanline time.
		 */
		u_int lineLen = bp - bol;
		if ((fp + fxmax(lineLen, minLen) >= eoFill) && (fp-fill != 0)) {
		    /*
		     * Not enough space for this scanline, flush
		     * the current data and reset the pointer into
		     * the zero fill buffer.
		     */
		    rc = sendPageData(fill, fp-fill, bitrev, (params.ec != EC_DISABLE), emsg);
		    fp = fill;
		    if (!rc)			// error writing data
			break;
		}
		if (lineLen >= minLen*rowsperstrip) {
		    /*
		     * The fill buffer is smaller than this
		     * scanline alone.  Flush this scanline
		     * also.  lineLen is greater than minLen.
		     */
		    rc = sendPageData(bol, lineLen, bitrev, (params.ec != EC_DISABLE), emsg);
		    if (!rc)			// error writing
			break;
		} else {
		    memcpy(fp, bol, lineLen);	// first part of line
		    fp += lineLen;
		    if (lineLen < minLen) {		// must zero-fill
			u_int zeroLen = minLen - lineLen;
                	if ( foundEOL ) {
                	    memset(fp-1, 0, zeroLen);	// zero padding
			    fp += zeroLen;
			    fp[-1] = bp[-1];		// last byte in EOL
			} else {
			    /*
			     * Last line does not contain EOL
			     */
			    memset(fp, 0, zeroLen);	// zero padding
			    fp += zeroLen;
			}
		    }
		}
	    } while (bp < ep);
	    /*
	     * Flush anything that was not sent above.
	     */
	    if (fp > fill && rc)
		rc = sendPageData(fill, fp-fill, bitrev, (params.ec != EC_DISABLE), emsg);
	    delete fill;
	} else {
	    /*
	     * No EOL-padding needed, just jam the bytes.
	     */
	    rc = sendPageData(dp, (u_int) totdata, bitrev, (params.ec != EC_DISABLE), emsg);
	}
	delete data;
    }
    if (rc || abortRequested())
	rc = sendRTC(params, ppmcmd, lastbyte, rowsperstrip, emsg);
    protoTrace("SEND end page");
    if (params.ec == EC_DISABLE) {
	// these were already done by ECM protocol
	if (rc) {
	    /*
	     * Wait for transmit buffer to empty.
	     */
	    ATResponse r;
	    while ((r = atResponse(rbuf, getDataTimeout())) == AT_OTHER)
		;
	    rc = (r == AT_OK);
	}
	if (flowControl == FLOW_XONXOFF)
	    setXONXOFF(FLOW_NONE, FLOW_NONE, ACT_DRAIN);
    }
    if (!rc && (emsg == "")) {
	emsg = "Unspecified Transmit Phase C error";	// XXX
    	protoTrace(emsg);
    }
    return (rc);
}

/*
 * Send the post-page-message and wait for a response.
 */
bool
Class1Modem::sendPPM(u_int ppm, HDLCFrame& mcf, fxStr& emsg)
{
    for (int t = 0; t < 3; t++) {
	tracePPM("SEND send", ppm);
	if (transmitFrame(ppm|FCF_SNDR) && recvFrame(mcf, FCF_SNDR, conf.t4Timer))
	    return (true);
	if (abortRequested())
	    return (false);
    }
    switch (ppm) {
	case FCF_MPS:
	    emsg = "No response to MPS repeated 3 tries";
	    break;
	case FCF_EOP:
	    emsg = "No response to EOP repeated 3 tries";
	    break;
	case FCF_EOM:
	    emsg = "No response to EOM repeated 3 tries";
	    break;
	default:
	    emsg = "No response to PPM repeated 3 tries";
	    break;
    }
    protoTrace(emsg);
    return (false);
}

/*
 * Terminate a send session.
 */
void
Class1Modem::sendEnd()
{
    transmitFrame(FCF_DCN|FCF_SNDR);		// disconnect
    setInputBuffering(true);
}

/*
 * Abort an active send session.
 */
void
Class1Modem::sendAbort()
{
    // nothing to do--DCN gets sent in sendEnd
}
