Cut-offs

[admin_2]

You'd think from the subject of this post I was reffering to jeans that had been made into shorts. Nah . . Actually - working with build 2.4.5.73 NEC AD-120 product. I wanted your take on this: Intermittently, people are being cut-off when leaving a message on the system, does not happen all the time, sometimes on different phones, no pattern at all. When the cut-off happens, it is generally 5 or six seconds into a person leaving a message. Any thoughts o' mighty answer Monkey ?<br><br>Thanks,<br><br>Hensontech<br><br>

[#2]

My first guess would be this is a silence deteciton issue but I'll probably let one of the integration experts (i.e. Steve) chime in here on the possibilities.

If the db level for what we (or more to the point the Dialogic WAVE driver) think is silence is too high, if a person is not yacking loud enough or a line comes in too quiet (i.e. cell phones have problems here sometimes) then we'll think the person stopped talking and we'll terminate the recording and move on.

I'm assuming we just stop recording and advance to the "After message menu" and we're not just haning up on them entirely... that would be a completely different class of problem.

If it's silence detection we can crank the db level down as low as -50 db but if you make it TOO quiet then we'll never stop recording if a person stops talking.


Jeff Lindborg
Unity Product Architect/Answer Monkey
Cisco Systems
lindborg@cisco.com
http://www.AnswerMonkey.net (new page for Unity support tools and scripts)

[#3]

When the caller's are getting cut off, are they prompted by the voice mail system (something like "press blah blah to send your message"), or are they disconnected?

Steve Olivier
Software Engineer
Cisco Systems

[#4]

Yes, they are prompted "to listen to your message press...yada tada yada." There is no patern we can find as to when or why it happens.

[#5]

Short Answer: There is no equivalent setting for silence threshhold that is exposed to the user when doing the CallManager integration.

Long Answer: Today, silence detection is only applicable to incoming G.711 calls. There are actually two ways that "silence" can be reported. One is via a lack of RTP packets for a specified period of time. The other is through a series of RTP packets marked with "silence" for a specified period of time. Unfortunately, there isn't a way to determine which case generated the silence event to the TSP's request to monitor for silence.

Recommendation:
For your case, we'll need more info: Does this happen to internal callers? External callers? Both? Does increasing the recording timeouts on the SA configuration improve the behavior?

Steve Olivier
Software Engineer
Cisco Systems

[#6]

It only happens to external callers. I have increased the "long recording time out" in SA to 4 seconds to see if that helps. Will let you know how it works out. Any other things I might try if it doesn't?

[#7]

You might want to take a look at the Gateway and see if there is any type of Silence Supppression enabled. Silence surpression basically stops sending RTP packets when a caller pauses when talking (thus, qualifying for one of the wav driver's criteria to report silence to the TSP). I curious to know if that's possible on the GW. It might only be possible when the calling party is also on an IP phone. Keith, Dustin, can you guys help me out here?

Steve Olivier
Software Engineer
Cisco Systems

[#8]

The Gateway is a VG-200. Codec is G711. I don't see anything in the config that indicates silence suppression, but I can e-mail you the config if you want to take a look at it.

[#9]

Sure. Send it to oliviers@cisco.com.

Steve Olivier
Software Engineer
Cisco Systems

[heyligerb]

I am curious to know if anyone ever got this problem solved? I had the same problem as well but I was having other problems too so I just rebuilt the whole box and that fixed the problem. But I would like to know the cause and fix incase I run accross this again.

Thanks,

Brian Heyliger
heyligerb@telecomsys.com
Systems Analysts

[#11]

As far as I know, the problem was not resolved. The only way will be able to know what was causing the problem is likely with an open TAC case so traces can be gerenated and engineers can review the traces.

Steve Olivier
Software Engineer
Cisco Systems

[#12]

The problem has not been resolved. We checked VAD on the VOIP Gateway, and it is disabled so that is not the cause. I will open a case with TAC to enable the tracing that you mentioned.

[kechambe]

A typical conversation may contain 35-50% silence. Using Voice Activity Detection (VAD), silence packets are suppressed thus saving bandwidth. On the flip side VAD is not perfect. VAD uses a threshold to determine what is silence and what is not. So if a caller is recording a message and falls below the threshold for too long the WAV driver will believe the user is done talking and Unity will stop recording and then prompt the users with the advanced message options.

VAD is also the number one cause of clipping complaints on the CallManager side of the house. I recommend that every reseller turn it off to avoid customer complaints.

VAD is configured by default under the voip dial-peers on Call IOS gateways. To disable VAD, use the command 'no vad' under the desired voip dial-peers.

Keith

Keith Chambers
Unity Technical Lead
Unified Voice Team, San Jose
Cisco Systems
kechambe@cisco.com

[#14]

First, thanks to both of you for your help. Yes, they are getting the ' After message menu ' after a cut-off. Where do I specify the DB level for the dialogic ? I have looked in the SA under >System>Configuration>Recordings and there is some stuff there but I did not see anything on ajusting the db level itself.

Once again - Thanks. If I lived in Seattle, I'd owe you guys lunch.

-Hensontech

[#15]

It's actually set in Dialogic-land. There is a description on how to adjust the quiet parameters in the Unity trouble-shooting guide. It's in chapter 4 "Messages".

Steve Olivier
Software Engineer
Cisco Systems