dialogic 摘挂机的检测.doc

Disconnect Supervision

When the caller hangs up, Dialogic card does not detect the disconnection. Why?

Most of the PBXs and switches today do not use loop current drop to notify the other party of the disconnection. Instead,
They use "disconnect tone", which is usually the same as busy tone. Disconnect tone will be sent to the called party as soon as
the calling party hangs up. For local calls, however, the disconnect tone is usually sent to the calling party 30 seconds after the
called party hangs up.

Dialogic cards, by default, is enabled to detect loop current drop. However, disconnect tone supervision is not enabled.

How to implement Disconnect Tone Supervision?

There are two ways of implementation:

Advanced Tone Feature (driver approach)

Global Tone Detection (application approach)

1. Advanced Tone Feature

This feature is currently available on DOS, Windows 95 and Windows NT (Streams version SDK only). This method makes
use of Tone Set File created by PBXpert or PBXpert/32. By simply using appropriate TSF file, you can make your system to
work on any analog switches or PBXs. To enable this feature, do the following:

For Windows NT:

Click Start/Programs/Dialogic System Software/Advanced Tone Features program item. Then tick Disconnect Tone
Supervision and Tone Set File Enabled buttons on the Advanced Tone Features window. Lastly, specify the TSF file to be
used.

For Windows 95:

Similar to that of Windows NT. The path is Start/Programs/Dialogic Development Package/Configuration Manager. Then
click Advanced button on the Dialogic Configuration Manager window.

For DOS:

After Dialogic voice driver is loaded, run TONEDNLD.EXE program to overwrite the default tone definitions contained in the
driver with those contained in the TSF file.

genload

d40drv -h<hardware interrupt>

TONEDNLD -f<path><filename.tsf> -h<hardware interrupt>

After ATF is enabled, the default tone definitions contained in the driver are overwritten with those contained in the TSF file.
When the disconnect tone is detected, an LCOFF event will be generated, as if it is a loop current drop event. The example
in asynchronous callback model below shows how to terminate dx_play() function upon detection of disconnect tone.

void start_playback (int index) {

DV_TPT tpt[1] = {0};

dx_clrtpt(tpt,1);

tpt[0].tp_type = IO_EOT;

tpt[0].tp_termno = DX_LCOFF;

tpt[0].tp_length = 1;

tpt[0].tp_flags = TF_LCOFF;

:

if (dx_play(Channel[index].voxhdl, &Channel[index].iott, tpt, EV_ASYNC) == -1) {

:

}

int play_handler (void) {

:

device = sr_getevtdev(0);

cause = ATDX_TERMMSK(device);

if (cause & TM_LCOFF){

printf("Play terminated due to Loop Current Drop\n");

disconnect(device);

:

}

Make sure you do not enable DM_LCOFF with dx_setevtmsk(), otherwise TDX_CST event will be generated and captured
by CST handler.

2. Global Tone Detection

This approach can be used in all platforms. You need to add codes into your application to detect the specified disconnect
tone(s). To make your application more portable across PBXs, I suggest that you make your application read a parameter file
in which the disconnect tone definitions is defined. The example below shows you how to do it:

#define POTS_DISCTONE 201

void main(int argc, char *argv[]) {

:

for(n=0; n<NumOfChannels; n++)

if (dx_deltones(Channel[n].voxhdl) == -1)

process_error(Channel[n].voxhdl, "dx_deltones");

// Singapore disconnect tone 425 Hz, 750 ms on, 750 ms off

if (dx_bldstcad(POTS_DISCTONE,425,30,75,6,75,6,2) == -1)

process_error(Channel[n].voxhdl, "dx_bldstcad");

for(n=0; n<NumOfChannels; n++)

if (dx_addtone(Channel[n].voxhdl,NULL,0) == -1)

process_error(Channel[n].voxhdl,"dx_addtone");

:

}

You can disconnect the line either with TPT or CST handler.

2.1 Use TPT to terminate playback or recording then disconnect the line.

void start_playback (int index) {

DV_TPT tpt[1] = {0};

dx_clrtpt(tpt,1);

tpt[0].tp_type = IO_EOT;

tpt[0].tp_termno = DX_TONE;

tpt[0].tp_length = POTS_DISCTONE;

tpt[0].tp_flags = TF_TONE;

tpt[0].tp_data = DX_TONEON;

:

if (dx_play(Channel[index].voxhdl, &Channel[index].iott, tpt, EV_ASYNC) == -1) {

:

}

int play_handler (void) {

:

device = sr_getevtdev(0);

cause = ATDX_TERMMSK(device);

if (cause & TM_TONE){

printf("Play terminated due to Loop Current Drop\n");

disconnect(device);

:

}

2.2 Use CST handler to disconnect the line.

int cst_hndlr(void) {

DX_CST *cstp;

device = sr_getevtdev(0);

cstp = sr_getevtdatap(0);

switch (cstp->cst_event){

case DE_TONEON:

if (cstp->cst_data == POTS_DISCTONE) {

voxstate = ATDX_STATE(device);

if ((voxstate==CS_PLAY)||(voxstate==CS_RECD)) {

/* if in record or play, stop activity on voice channel*/

if (dx_stopch(device, EV_ASYNC)==-1)

printf("ERROR: dx_stopch() failed\n");

}

disconnect(device);

:

}

Attachments:

Demo program

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