Making Two-Channel Call Transfers (Tromboning)

When the application creates a two-channel call transfer, the two callers become sources of the reflected data. The application must configure the echo cancellation portion of the channel resource to remove repeated input from two sources by using its reference signal slot (the channel’s reference number is 1). The application must also call the BfvSpeechEchoCancelControl() function to configure the channel to accept an input reference signal on slot #1.

For example, your application could create a connection from the output slot of Network resource 1 to the reference input slot of Channel 0 by calling the BfvSpeechEchoCancelControl() and BfvCallSWConnect() functions with the following arguments:

BT_ZERO(speech_args);

/* Configure channel to get its input reference signal from slot #1. */ Speech_args.echoc_op = ECHOC_OP_ALT_INPUT_ENABLE; BfvSpeechEchoCancelControl (lp, &speech_args);

BT_ZERO(args);

args.conn_mode = CALL_SW_TRANSMIT_ONLY_DEF; args.src_port_class = CALL_SW_PORT_NETWORK_DEF; args.src_port_unit = 0;

args.src_stream = 0;

args.src_slot = 1; /* Network Timeslot */ args.dest_port_class = CALL_SW_PORT_CHANNEL_DEF; args.dest_port_unit = 2; /* Logical DSP Channel Number */ args.dest_stream = 0;

args.dest_slot = 1; /* Reference Slot */ BfvCallSWConnect (lp, &args);

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Dialogic 6.2 manual November 195