atcomsystems.ca/forum Forums TDM Business Telephone Systems NEC Telephones & Systems NECSL2100

We have a customer that has the NECSL2100. The problem they are having is a bit bizare. There is not any set time during the day that this happens but there are times that they will get several messages in the voicemail box but all the messages are dead air. The calls appear to be 30 seconds apart. Any suggestions?

There are times that when you call the main number it will just ring and won't go to voicemail. In this instance it was after hours. Once the customer rebooted the system it resolved itself and went to voicemail.

We have checked with the local telco, its a fiber connection and line, equipment have all been checked. It seems to all point to the phone system but at a loss?

Have you ran the side tone adjustment tests on all the lines? 90-68

You mention "the voicemail box". Which voicemail box is it, and what has to happen to get a call routed there? This may lend a clue to what type of call you are getting. Cross ref the timestamps on the dead air msgs against the Call Log. That said, I agree with oobie, 90-68 is a must first.

Are these POTS lines?

In case this helps:

I had the same thing happen to me. SL2100, just installed. POTS lines. I had done the line calibration already, and it had a fresh restart. Came back a couple days later to see how things were going, and they tell me ext 101 had 99 messages from two phone numbers. Every message was 4 minutes apart with no audio or actual message. 99 is the max number of messages as set in 47-02.

This happened overnight, with auto attendant answering. One of the calls was me, checking out the DAT choices and routing, and I did not leave a message.

I cleared out all messages and its been ok since.

Jim

I have a SL2100 that is doing the same thing but with a twist. This system has 8 CO Trunk Line through a
Comcast Modem. It first started with Line 1 (only did it once) in coming calls would just ring, AA would not
answer. Line showed it was in use but when I checked with my butt set on the block no conversation but
had dial tone. To clear had to reboot the system.

Two days later it again happened this time on Line 2. Same parameters, had to reboot again. This time after much
discussion with Tech Support I first called Comcast and told that it is a phone system issue "not their modem". I asked
for the specs on the "Open Loop" timer and was told it was 500ms. Further discussions with Tech Support it was
decided that I should change 81-01-03 to 400ms. Made the change.

To test I would dial in over the next few days on lines 1-4 and always got the AA. That was 2 weeks ago. All has
been good until yesterday. I was on site and noticed that Line 3 was lit on the phone. I checked and the same
issue. After much discussion with Tech Support it is unclear as to what is causing the problem and what would
be the next logical step to try and resolve.

In an effort to get other opinions I came here. So are there any thoughts or suggestions??
I am happy that at least one other (RWG) has experienced this condition. I don't fell all alone................

Thanks for any input.

Les

This is almost ALWAYS a disconnect supervision issue. What I have done on this and other systems is change the AA to timeout to hangup and change the greeting so they have to press a key to leave a message. Only ever seems to be an issue with analog lines, especially off an EMTA or IAD.

Hi Coral Tech,

Thanks for the quick response.

When you say it "Only ever seems to be an issue with analog lines, especially off an EMTA or IAD."

Would you please define EMTA and IAD??

Per your suggestion I will change the timeout to hangup and see if that will help.

Thanks,

Les

EMTA proprietary device used by cable companies to provide analog lines. IAD, Integrated access device used with T1's or other voip service that can break out analog lines etc.

Hi Coral Tech,

Ok, so then the "Comcast Modem" as I call, it is the EMTA that is providing the actual
dial tones to the system. And it is that device that is causing the problem with the lines "locking up".

This morning I changed 47-13 Dial Action Table AA from a "repeat of the AA message" to "Hangup"
if no response from the caller. I also changed the 81-01-03 to 450ms from the previous setting of 400ms.
Hopefully one or both of those setting will make the difference.

So that I understand it better can you explain why this happens with these EMTA's??

Is it due to the components are a bit out of spec with the firmware in that some are not providing the
actual 500ms Open Loop as it was designed consistently??

Or does it have something to do with a specific KSU and a specific EMTA that they just can't get along
in the same bed together??

This is my first experience with this issue (which isn't saying much) and I am trying to understand the
dynamics of the problem I am getting the feeling that the odds of it happening is very small.
But, it would seem to me that the mfg of EMTA's and KSU would know it exist and could easily provide
a permanent fix so that it won't happen again.

Or am I missing something that is behind DOOR #2??

Again thanks for any input.

Les

As a side note: Where do I go in this forum to change the setting so that I can get a email
when a new message is posted to this thread??