Hello,
A client of ours has an NEC 2000 IPS. They also have AT&T IP Flex service. Here is the issue we are having:

1- We installed an MoH player
2- loaded the MoH player with one audio file that included several voice paragraphs with background music between paragraphs
3- The audio file was formatted and created as one audio file
4- When placed on hold: The voice portion plays crystal clear, but the Music portion plays distorted, muffled, and kind of staticky.

Questions:
1- What is the cause and how can we correct the issues during the "Music" portion playback?
2- Does anyone know if the NEC 2000 IPS supports storing and playing MoH audio files internally? If so, then what is the supported file format and how do you load it onto the phone system?

Thank you

Ollie North
Spectrio; LLC
800-584-4653 Ext 6440

I think your going to find the same solution you had with the SL1100 from your previous post.

Has nothing to do with the phone system.
Its voice versus music and the frequency of audio your inputting to the phone system.

Same story, different day.

If you had an analog trunk to system i don't think any problem with it. One major advantage of a POTS line.

Again keep this in mind before causing your self some head aches.

We never found a solution, we ended up not loading music...Just voice! The NEC phone system is the only phone system we've ever experienced this issue with. We use standard MoH equipment across the board and we follow the manufacturer's file formatting guidelines. To me, it sounds like the phone system is having an issue processing and distinguishing between voice and music, so it is making "Its own adjustment" resulting in the distorsion we are hearing during music playback. We have already tried many different music compression and frequencies, but so far the distorsion still remains

Does the NEC 2000 has automatic audio volume amplification feature?

What are you running it at 600 Ohm mono?

Did you sample the audio coming out of the telephone set coming
from output of the BGM feature of the telephone ?

Coral Tech:
We tried it at both 600 OHM & 8 OHM with no difference

TJ:
We have not sampled the audio while the BGM feature is turned on at a phone set. We can run such test today.

Here is some new information I just received from another technician:

“Ok so I checked and if you are using g728, g729 or g729a you will have issues with distorted music as the codecs use a sort of human voice cookbook to achieve the compression rates and it is a known problem with music and more specifically music on hold! Problem is that if it passes through any link using these codecs, you will experience this problem (sometimes it can be so bad all you hear is a hissing)!”

Is there a known fix to such problem?
Also, what does "G728, G729, G729a" stand for? Where do you confirm on the phone system if it has one of them?

Thank you

G728, G729, and G729a are audio compression codecs used by a VoIP connection. Audio compression, as the link you quoted says, is designed around human voice. Anything else will be distorted. These particular codecs are the maximum compression possible -- a 64K (56K + 8K overhead) stream is compresses to about 8K + 8K overhead, if I recall correctly.

Setting up the compression characteristics of the phone line (the code-decode) is something that will have to be negotiated between the phone company, the client, and the phone vendor.

The answer is and the only answer, you need to use POTS lines.
Mystery solved and again i say it has nothing to do with the phone system or just because it is NEC. Your problem is what kind of phone lines are servicing the customer period. They are on IP/VOIP or what ever based on what you have communicated on
your post.

Thank you all very much for your replies, I have learned so much about this issue today.

Actually not quite correct there, There is absolutely nothing wrong with Voip per se. The customer simply has to make an informed decision on compression as you wouldn't have these problems with other codecs that don't give as much compression.

Strange to see myself being quoted! :-)

Regards

R4 AKA OzzieGeorge

True, but I often find that the end user doesn't know what to ask for when selecting service providers; they are only shopping price or falling for a good sales pitch.

Everyone here who knows anything about VoIP knows that the compression (sampling) rate of digitized sound varies greatly. Voice traffic is choppy and easily patched back together at even the worst sampling rate, yet smooth/constant sounds as with music are nearly impossible to recreate. This is perhaps the easiest way to detect a cheap deal on the service provider.

I find that calling and listening to music on hold is the easiest way to tell just how well the service provider is doing. Calling a fax or modem is also a good indicator. If you are able to hear the tones without distortion, then they are doing a good job.

Oh, and as it was said earlier, this issue has nothing to do with the brand or model of the phone system.

Thank you Mr. ED. It is what it is.Lets all come to reality and have a good holiday.

I don't think that people even realize that different codecs can respond differently to different languages. We are in a new head space and at the moment, most customers who are switching to Voip are not aware of the new landscape. I think the companies who are up front and can weather the storm will come out stronger than ever, but too many companies are more interested in sales than customer retention!

I completely agree that this is not a vendor related problem, it is a standards problem, well actually not even standards related. It is customer decision related but the problem is, nobody is telling the customer that they even have this decision to make and what the consequences are!

agree! I Feel the selling agent should be responsible for education of the end user. This day and age seems like most don't really care or have the knowledge to educate the end user.....

Music on hold over VoIP... never sounds correct.

D