Intermittent Silence Issue

[Guest miva]

Hi,

 

We've had reports from customers of silent calls, they ring and connect with the system but there are no prompts, only silence. Yesterday I managed to replicate the problem, I rang the system and could see the connected call in the status monitor, my phone showed I was connected, but all that played was silence. I waited around 30 seconds and then pressed key 2 which starts a sub script and plays different messages, but still all I heard was silence. The system detected the key press and I can see in the log file it says it was playing the messages.

 

The messages all work and on subsequent phone calls they played correctly on the same server and dialogics card (only 1 installed on the system).

 

We are using VG 7.3.4391.19239 (RELEASE Build) and I have attached an excerpt from the logs for your review.

 

Thanks,

Ben.

Example.zip

[SupportTeam]

Traces shows that the Dialogic card reported that playing has commenced with no errors, and that playing was continuing for the 30 seconds, after which if was stopped with no errors when the PlayStop command was issued to the card by VoiceGuide (after the DTMF keypress was detected).

 

 

 

095234.953 1980 43 fn PlayStart(iLineId=43, sFileList=,C:\Program Files\VoiceGuide\Scripts\MCR\Actron\Actron-IVR\Silence.wav,C:\Program Files\VoiceGuide\Scripts\MCR\Actron\Audio\msg1.wav, sXMLOptions=)

095234.953 1980 wav: format=7, channels=1, hz=8000, bytes/sec=8000, bytes/sample=1, bits/sample=8, DataBlockSize=8534 C:\Program Files\VoiceGuide\Scripts\MCR\Actron\Actron-IVR\Silence.wav

095234.953 1980 wav: format=7, channels=1, hz=8000, bytes/sec=8000, bytes/sample=1, bits/sample=8, DataBlockSize=338557 C:\Program Files\VoiceGuide\Scripts\MCR\Actron\Audio\msg1.wav

095234.953 1980 43 play(45, 0x15f60e30, tpt=0x0, xpb=0xf73bc60) => 0, hli=0F737FB8

 

095302.796 3812 43 r dtmf 2

095302.812 1980 43 fn PlayStop(iLineId=43, iActionID=0, iParam1=0, iParam1=0, sParam1=, sParam1=)

095302.828 3812 45 ev TDX_PLAY (Play Completed)

 

 

 

So either the Dialogic card is faulty or (more likely) the voice path is not always connected to the caller when the call is connected (which would be Telco problem).

 

This looks like a T1/E1 ISDN trunk based system. At the trunks plugged into Dialogic card come straight fro Telco, or do they go through some switch or media converter?

 

Are you able to determine if problem is occurring on one channel only, or whether is occurs on various channels?

You can probably identify which calls were problem calls by their length reported in CDR logs. The calls where caller hung up as they could not hear anything would have a short length.

[Guest miva]

Yes it is an ISDN based trunk. The building is cabled with fibre optics, so there is some sort of converter installed to deliver the ISDN via the fibre optics.

 

Not sure if it is specific to one channel or not, but will conduct more testing. It took us around 80 test calls yesterday to replicate the fault. Not frequent but enough that customers complain about the issue.

[SupportTeam]

Fibreoptic media converters would usually convert the entire ISDN trunk signal, without caring what traffic is carried on individual channels within trunk. The type of converters that could affect one side of voice path would be ones that take individual calls and covert/route them on a per-call basis. Eg. ISDN<->VoIP media converters.

 

If by studying the logs you conclude that this issue is linked to specific channel then most likely there is a hardware problem at either Telco switch or the Dialogic card.

 

Dialogic T1/E1 cards can be tested if you have another telephony card and connect them back-to-back using a cross-over cable.

One approach is to have the card that is being tested play a sound file that has a series of DTMF tones recorded in it, and the testing card is used to detect the DTMF tones, this then confirms the sound file was played properly.

[Guest miva]

Ok thanks, the cross-over cable sounds like the best method for load testing. Do you happen to know the pin-out for the cable?

[SupportTeam]

Please see: http://www.dialogic.com/webhelp/IMG1010/10.5.2/WebHelp/rj_48_pinouts_1004.htm