Merlin Magix/Legend Microphone Volume

[jlexer]

After a physical office move to a new location. Parties that call us (or we call out) report that they can hardly hear us. After some testing, it appears that if the speaker's mouth is beyond 1-2 cm from the microphone the volume is totally eliminated. If the speaker's mouth is directly up the the microphone, the volume is fine. If the speaker uses the speakerphone feature, the volume is appropriate to a speaker phone conversation, so we do not believe that it is a wiring issue.

We made no configuration changes in the physical office move. Just moved the cabinet and phones to the new office and connected to the exact same number and configuration of POTS lines.

Config:
Avaya / Lucent Merlin Magix R4 Processor
3 408 MLX Merlin Legend 408 GS/LS-MLX Module
16 MLX-10DP
1 MLX-20L

The issue is the same whether the 10DP or 20L.

Is there some kind of global or individual microphone gain setting. It seems highly unlikely that all of our handsets are dying at the same time.

 

[merlinman]

The main commonality of such an issue could very well be the Power from the wall.

I would look into that.

But first, I would make a few test calls in house between a few phones and see if the problem is also happening on calls not going outside.

If it is happening only on Outside calls, then I would suspect a transmission problem from your provider.

http://home.comcast.net/~merlinman

-merlinmansblog.blogspot.com

 

[jlexer]

Just tested and confirmed. There is definitely no problem at all when making internal calls. The speaker's mouth was a good 10" away from the microphone and it sounds just as clear as 1" from the microphone.

Are you saying that I should next to try plug the PBX into a different electrical outlet to see if there is a difference?

As far as the Phone provider, what should I be requesting that they perform to test the lines?

 

[merlinman]

As far as the Power Source (AC) that would have to be measured with a VOM.

The vendor should be told that since the move, people on the outside cannot hear you very well. Then ask if they can do a TRANSMISSION TEST on the lines.

There is a way they can measure the voice quality & level on their lines.

http://home.comcast.net/~merlinman

-merlinmansblog.blogspot.com

 

[jlexer]

Spoke with the phone company and they stated that the lines test fine. They also had me plug a standard (non-pbx) phone directly into one of the incoming lines. I then made a call with this phone and confirmed that the person speaking did not need to have their mouth pressed up to the microphone as is the case for the pbx calls.

This would indicate (to me at least) that the problem is in the pbx, or at least somewhere behind the pbx in the chain of equipment.

If this helps, I noticed on the front of the power supply module, there is a ground screw. It was never connected to any ground wire at our old office and it worked fine. Could it help to ground it now?

Any other suggestions?

 

[Telecomboy]

I would test each line individually to see if there is one or two problem lines or if they all have an issue. Each Merlin 408 MLX card has 4 lines connected to it. If you notice 4 lines that are all on the same card have an issue, you know it is an issue with that card. It could be when you moved the 408 cards were mixed up in their order and that's why you now notice it. That card may not have been used before (for lines).

 

[SYQUEST]

When the telco "tested" the lines, did they actually send someone out with a meter to measure the loop loss of each line? Just saying they are fine is not a measurement of loop loss or transmission!

It is possible that one or more of the line ports on one of the 408MLX modules is defective. So you may need to do testing of those to isolate the bad ones per Telecomboy's suggestion above.

As far as system grounding is concerned, the ground terminals should be connected to the appropriate termination per the Avaya installation document and NEC codes. If you don't have the Avaya document, you can download it for free from support.avaya.com . There is a maintenance document available also for your reading enjoyment.

....JIM....

 

[jlexer]

Here is the current status:

I've tested the receptacle output and it reads at 120.6 V +/- .2 during a two minute time period.

I attached a 12ga ground cable from the front of the power supply module to the receptacle... no change.

I tested each line individually by connecting a non-pbx phone directly to each line in the wiring closet. They all sound fine when calls are made from in front of the pbx.

I am certain that I have all of the 408 modules in the correct (and the same as prior to the move) order because they are all sequentially numbered.

Any other suggestions?

 

[SYQUEST]

Yes, you did not answer the question I asked above!

....JIM....

 

[jlexer]

Syquest: sorry, I did not see your reply before I added my post. The phone company has not physically tested the lines onsite. They only tested from their office while I was on the line with them. They have offered to send a tech, but since they feel there is nothing wrong on their end, if they do not find a problem with their equipment they are going to charge us a $200 service call fee. Since the volume seems fine when using a non-pbx phone directly attached to the lines, I feel they are just going to tell me that there is no problem and I'll incur the fee.

Is the loop loss test something that I can do with a multimeter? If not, is there some meter that I can buy or rent to test the lines while we are on the calls (both with the pbx and in-front of the pbx)?

 

[SYQUEST]

No, a TMS, or transmission measurement set,(also called a TIMMS, transmission impairment measurement set) is a specialized meter for troubleshooting analogue lines/circuits. They can be purchased or rented. The testing process uses specific steps to measure transmission loss, noise, balance, return loss, etc. using Telco milliwatt and silent termination ports for PBX and pots lines. To do end-to-end testing on point-to-point circuits, you would have a TMS on each end.

....JIM....