[VoiceOps] Call quality issue / survey

Hiers, David David.Hiers at adp.com
Mon Mar 11 18:02:39 EDT 2013

I'm going to Disneyland!


Bad quality into an entire rate center?  What's it like coming out of that rate center?

I've had a broad problem that turned out to be a particular tandem carrier.  They were the cheap way into RCx, and all calls into RCx were bad.   


-----Original Message-----
From: Nathan Anderson [mailto:nathana at fsr.com] 
Sent: Monday, March 11, 2013 14:32
To: Hiers, David (DS)
Cc: 'voiceops at voiceops.org'
Subject: RE: [VoiceOps] Call quality issue / survey

On Monday, March 11, 2013 6:45 AM, Hiers, David <mailto:David.Hiers at adp.com> wrote:

> 208-301-5083: Good quality. Sounds like a waveform codec.
> 208-301-5084: Mostly unacceptable quality. Sounds like a vocoder codec.

*ding* *ding* *ding*!  We have a winner!  (Runner-up goes to Jared who also touched on the codec issue.)

Although everybody picked the same recording in the end, what David points out is exactly what I had noticed and was looking for in the responses: one sounded like a land-line.  The other sounded like a bad cell phone call.  This is why I was encouraging people to NOT run the test from a cell phone: because you'd be on the receiving end of an actual voice-optimized codec, which would mask the issue somewhat.

In response to Jared's comment that...

On Saturday, March 09, 2013 9:40 AM, Jared Geiger <> wrote:

> [...] neither seemed to have the warmth and clarity I would expect 
> from a full ulaw path the whole way through.

...I suspect that is partly an issue with the source material.  And who knows what kind of equipment the end-user has or how it is hooked up to the telco (iffy analog loops?).  But there are no noticeable compression artifacts when you listen to the one from 5083, and there are in the 5084 recording.  This is despite the fact that the audio stream that was delivered to us was, in fact, G.711u.  Somehow, some way, the audio stream is getting encoded with a lossy compression scheme of some kind, and then transcoded back to G.711u before being handed off to us.

I suspect more is going on here, though, than the simple transcoding (although that is obviously part of it).  The long connection times, the annoyingly loud "pop" at the beginning of the call when it's finally being connected, occasional scratchiness/static on the line, inconsistent volume levels during a call, wildly inconsistent volume levels *between* calls (some are super-low the entire time)...these are all problems that we are regularly and constantly seeing with calls to this entire rate center as a whole.

The person who initially responded to my ticket about this said he couldn't hear the issue, thus this post.  I wanted to know whether I was crazy or not.

Nathan Anderson
First Step Internet, LLC
nathana at fsr.com

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