#include <t38_core.h>

Public Attributes
t38_tx_packet_handler_t	tx_packet_handler
	Handler routine to transmit IFP packets generated by the T.38 protocol engine.
void *	tx_packet_user_data
	An opaque pointer passed to tx_packet_handler.
t38_rx_indicator_handler_t	rx_indicator_handler
	Handler routine to process received indicator packets.
t38_rx_data_handler_t	rx_data_handler
	Handler routine to process received data packets.
t38_rx_missing_handler_t	rx_missing_handler
	Handler routine to process the missing packet condition.
void *	rx_user_data
	An opaque pointer passed to any of the above receive handling routines.
int	microseconds_per_tx_chunk
	Required time between T.38 transmissions, in us.
int	chunking_modes
	Bit fields controlling the way data is packed into chunks for transmission.
int	iaf
	Internet Aware FAX mode bit mask.
int	data_rate_management_method
	Method 1: Local generation of TCF (required for use with TCP). Method 2: Transfer of TCF is required for use with UDP (UDPTL or RTP). Method 2 is not recommended for use with TCP.
int	data_transport_protocol
	The emitting gateway may indicate a preference for either UDP/UDPTL, or UDP/RTP, or TCP for transport of T.38 IFP Packets. The receiving device selects the transport protocol.
int	fill_bit_removal
	Indicates the capability to remove and insert fill bits in Phase C, non-ECM data to reduce bandwidth in the packet network.
int	mmr_transcoding
	Indicates the ability to convert to/from MMR from/to the line format to improve the compression of the data, and reduce the bandwidth, in the packet network.
int	jbig_transcoding
	Indicates the ability to convert to/from JBIG to reduce bandwidth.
int	max_buffer_size
	For UDP (UDPTL or RTP) modes, this option indicates the maximum number of octets that can be stored on the remote device before an overflow condition occurs. It is the responsibility of the transmitting application to limit the transfer rate to prevent an overflow. The negotiated data rate should be used to determine the rate at which data is being removed from the buffer.
int	max_datagram_size
	This option indicates the maximum size of a UDPTL packet or the maximum size of the payload within an RTP packet that can be accepted by the remote device.
int	t38_version
	This is the version number of ITU-T Rec. T.38. New versions shall be compatible with previous versions.
int	allow_for_tep
	Allow time for TEP playout.
int	fastest_image_data_rate
	The fastest data rate supported by the T.38 channel.
int	pace_transmission
	Pace transmission.
bool	check_sequence_numbers
	True if IFP packet sequence numbers are relevant. For some transports, like TPKT over TCP they are not relevent.
int	category_control [5]
	The number of times each packet type will be sent (low byte). The depth of redundancy (2nd byte). Higher numbers may increase reliability for UDP transmission. Zero is valid for the indicator packet category, to suppress all indicator packets (typicaly for TCP transmission).
int	tx_seq_no
	The sequence number for the next packet to be transmitted.
int	rx_expected_seq_no
	The sequence number expected in the next received packet.
int	current_rx_indicator
	The current receive indicator - i.e. the last indicator received.
int	current_rx_data_type
	The current receive data type - i.e. the last data type received.
int	current_rx_field_type
	The current receive field type - i.e. the last field_type received.
int	current_tx_indicator
	The current transmit indicator - i.e. the last indicator transmitted.
int	v34_rate
	The bit rate for V.34 operation.
int	missing_packets
logging_state_t	logging
	Error and flow logging control.

Detailed Description

Core T.38 state, common to all modes of T.38. Higher layers should support the specifics of a gateway, terminal, T.31 interface, etc and incorporate an instance of this structure to handle the basics of T.38, mostly IFP.

Member Data Documentation

◆ allow_for_tep

int t38_core_state_s::allow_for_tep

Allow time for TEP playout.

Referenced by t38_core_send_indicator(), and t38_set_tep_handling().

◆ category_control

int t38_core_state_s::category_control[5]

The number of times each packet type will be sent (low byte). The depth of redundancy (2nd byte). Higher numbers may increase reliability for UDP transmission. Zero is valid for the indicator packet category, to suppress all indicator packets (typicaly for TCP transmission).

Referenced by t38_core_init(), t38_core_send_data(), t38_core_send_data_multi_field(), t38_core_send_indicator(), and t38_set_redundancy_control().

◆ check_sequence_numbers

bool t38_core_state_s::check_sequence_numbers

True if IFP packet sequence numbers are relevant. For some transports, like TPKT over TCP they are not relevent.

Referenced by t38_core_init(), t38_core_rx_ifp_packet(), and t38_set_sequence_number_handling().

◆ chunking_modes

int t38_core_state_s::chunking_modes

Bit fields controlling the way data is packed into chunks for transmission.

Referenced by t38_terminal_set_config(), and t38_terminal_set_tep_mode().

◆ current_rx_data_type

int t38_core_state_s::current_rx_data_type

The current receive data type - i.e. the last data type received.

Referenced by t38_core_restart(), and t38_core_rx_ifp_stream().

◆ current_rx_field_type

int t38_core_state_s::current_rx_field_type

The current receive field type - i.e. the last field_type received.

Referenced by t38_core_restart(), and t38_core_rx_ifp_stream().

◆ current_rx_indicator

int t38_core_state_s::current_rx_indicator

The current receive indicator - i.e. the last indicator received.

Referenced by t38_core_restart(), and t38_core_rx_ifp_stream().

◆ current_tx_indicator

int t38_core_state_s::current_tx_indicator

The current transmit indicator - i.e. the last indicator transmitted.

Referenced by t38_core_restart(), and t38_core_send_indicator().

◆ data_rate_management_method

int t38_core_state_s::data_rate_management_method

Method 1: Local generation of TCF (required for use with TCP). Method 2: Transfer of TCF is required for use with UDP (UDPTL or RTP). Method 2 is not recommended for use with TCP.

NOTE - Bandwidth reduction shall only be done on suitable Phase C data, i.e., MH, MR and - in the case of transcoding to JBIG - MMR. MMR and JBIG require reliable data transport such as that provided by TCP. When transcoding is selected, it shall be applied to every suitable page in a call.

Referenced by t38_core_init(), and t38_set_data_rate_management_method().

◆ data_transport_protocol

int t38_core_state_s::data_transport_protocol

The emitting gateway may indicate a preference for either UDP/UDPTL, or UDP/RTP, or TCP for transport of T.38 IFP Packets. The receiving device selects the transport protocol.

Referenced by t38_core_init(), t38_core_rx_ifp_stream(), and t38_set_data_transport_protocol().

◆ fill_bit_removal

int t38_core_state_s::fill_bit_removal

Indicates the capability to remove and insert fill bits in Phase C, non-ECM data to reduce bandwidth in the packet network.

Referenced by t38_core_init(), and t38_set_fill_bit_removal().

◆ iaf

int t38_core_state_s::iaf

Internet Aware FAX mode bit mask.

Referenced by t38_terminal_init(), and t38_terminal_set_fill_bit_removal().

◆ jbig_transcoding

int t38_core_state_s::jbig_transcoding

Indicates the ability to convert to/from JBIG to reduce bandwidth.

Referenced by t38_core_init(), and t38_set_jbig_transcoding().

◆ logging

logging_state_t t38_core_state_s::logging

Error and flow logging control.

Referenced by t38_core_get_logging_state(), t38_core_init(), t38_core_rx_ifp_packet(), t38_core_rx_ifp_stream(), t38_core_send_data(), t38_core_send_data_multi_field(), and t38_core_send_indicator().

◆ max_buffer_size

int t38_core_state_s::max_buffer_size

For UDP (UDPTL or RTP) modes, this option indicates the maximum number of octets that can be stored on the remote device before an overflow condition occurs. It is the responsibility of the transmitting application to limit the transfer rate to prevent an overflow. The negotiated data rate should be used to determine the rate at which data is being removed from the buffer.

Referenced by t38_core_init(), and t38_set_max_buffer_size().

◆ max_datagram_size

int t38_core_state_s::max_datagram_size

This option indicates the maximum size of a UDPTL packet or the maximum size of the payload within an RTP packet that can be accepted by the remote device.

Referenced by t38_core_init(), and t38_set_max_datagram_size().

◆ microseconds_per_tx_chunk

int t38_core_state_s::microseconds_per_tx_chunk

Required time between T.38 transmissions, in us.

Referenced by t38_core_init(), t38_get_tx_packet_interval(), and t38_set_tx_packet_interval().

◆ missing_packets

int t38_core_state_s::missing_packets

A count of missing receive packets. This count might not be accurate if the received packet numbers jump wildly.

Referenced by t38_core_rx_ifp_packet().

◆ mmr_transcoding

int t38_core_state_s::mmr_transcoding

Indicates the ability to convert to/from MMR from/to the line format to improve the compression of the data, and reduce the bandwidth, in the packet network.

Referenced by t38_core_init(), and t38_set_mmr_transcoding().