Synthetic and robotic voice issues

Answered Question
Dec 31st, 2007

Hello, I have a remote site with a 3745. All the IP phones at that site register to a CM at the main site. So, outside calls come in on a BRI to the 3745, are PLARed to the CM across a WAN. The CM has a CTI Rt Point to the Unity AA. Sometimes, the outside callers here a robotic or synthetic voice during a little choppyness when the AA is playing. It doesn't happen all the time but enough to cause complaints.

When I do a show call active voice on the 3745, it shows gapfills and late packets. I always get that when I hear the synthetic voice. The call does go to the main site through a 6608 blade and I found a bug, CSCdx36894, which is applicable to CM ver 3.1.x. We are using CM 4.1.3 sr3a, Unity is 4.0.4 sr1. What else can I adjust to fix the synthetic voice? Thanks.

3745 stats:

GapFillWithSilence=950 ms *

GapFillWithPrediction=1980 ms *

GapFillWithInterpolation=0 ms

GapFillWithRedundancy=0 ms

HiWaterPlayoutDelay=350 ms

LoWaterPlayoutDelay=25 ms

ReceiveDelay=29 ms *

LostPackets=0

EarlyPackets=0

LatePackets=83

6608 module in switch:

Switch> (enable) show version 2

Mod Port Model Serial # Versions

--- ---- ------------------- ----------- --------------------------------------

2 8 WS-X6608-T1 SAD08140840 Hw : 1.5

Fw : 5.4(2)

Sw : 7.4(3)

HP1: D00404000022; DSP1: D0054322 (4.3.222)

HP2: D00404000022; DSP2: D0054322 (4.3.222)

HP3: C00104000001; DSP3: C002E031 (3.3.2)

HP4: C00104000001; DSP4: C002E031 (3.3.2)

HP5: C00104000001; DSP5: C002E031 (3.3.2)

HP6: C00104000001; DSP6: C002E031 (3.3.2)

HP7: C00104000001; DSP7: C002E031 (3.3.2)

HP8: C00104000001; DSP8: C002E031 (3.3.2)

I have this problem too.
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Correct Answer by Paolo Bevilacqua about 9 years 2 weeks ago

Hi,

do "clear counters" on both 3745 at the same time. Then the next day, or after experiencing voice quality issue, check the packets counter from "show atm pvc x/y" again on both routers. If output to input differs, the issue is there and you need to configure ATM and QoS properly.

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gogasca Mon, 12/31/2007 - 20:22

PSTN -- 6608 --- WAN --- 3725 -- BRI///

Where is Unity?

What is the call flow?

Call arrives at BRI or at 6608?

You can check QoS settings and try to use G.729 if it not configured.

d.anthony.hadley_2 Wed, 01/02/2008 - 05:43

Thanks for the response.

The call comes in on a BRI at the remote site, 3745, then ATM WAN to another 3745 then ATM WAN to 6608 blade in a 6503, then a 6509, 6509 to CallManager (CTI Rt Pt) to Unity Auto Attendant where callers enter an extension to reach the person at the remote site. So the flow back from the AA to the outside caller would be:

Unity AA- 6509-6509-6503/6608-WAN-3745-WAN-3745-BRI/PSTN

CallManager and Unity are connected to the 1st 5609

Correct Answer
Paolo Bevilacqua Wed, 01/02/2008 - 07:29

Hi,

do "clear counters" on both 3745 at the same time. Then the next day, or after experiencing voice quality issue, check the packets counter from "show atm pvc x/y" again on both routers. If output to input differs, the issue is there and you need to configure ATM and QoS properly.

d.anthony.hadley_2 Wed, 02/13/2008 - 13:08

This response is a little delayed but I wanted to show a resolution. I did the clear counters and found that the 3745 (between the two ATM WANs) was dropping packets going toward the 3745 with the BRI circuits, which is where the callers would here the AA prompt. By doing a "show atm vc x" I was able to correlate the dropped packet with the synthetic/choppy voice. That PVC is configured for UBR when all the others are configured for VBR. The circuit will need to be provisioned for VBR. I caught this a few days ago when the state had a primary election and the telco network was, apparently, very congested. Thanks.

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