Dialogic 6.2 用户手册

Making Two-Channel Call Transfers (Tromboning)

November 2009

195

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);