sundance-communications.com/forum Forums TDM Business Telephone Systems NEC Telephones & Systems DS2000 T1 incoming call drops and jittery winks

I've got a DS2000 with T1 card which has been working fairly reliably since it was installed in April 2004, and even better since 3.22.00 was installed in April 2005.

unfortunately for the last week it has been having handshake issues for incoming calls: I'll get ringing, but the line will be dead on pickup. the call will roll to the next trunk, and may go through the same process two or three times before finally getting connected. this of course is driving the receptionists nuts.

the system does show caller ID, so ANI and DNIS are coming through. the problem appears to be the off-hook handoff.

the phone company claims nothing has changed, and nothing on the system has changed since loading 3.22.00 in April.

the reccomendation he got from NEC was "update the firmware" so I did, to little effect. (although it is nice to finally have sidetone.)

the error counters on the T1 are completely clean. there's nothing wrong with the circuit. it appears to be an issue on the DS2000 itself. any further ideas to diagnose this before I order another T1 card to swap out?

>config

System building date and time
Mon Dec 11 13:19:20 2006

System Type: DS2000
Version : DS2000 VER 03.22.09(12/11/06)
Checksum : C3BA

Dsp : v04.15
Dsp-DBU : v04.28

System configuration
Slot CardType Version Condition Checksum ChecksumError
1 DSTU16 2.4 00 20cee1 ------
2 DSTU16 2.4 00 20cee1 ------
3 DSTU16 2.4 00 20cee1 ------
4 ASTU04 2.5 00 ------ ------
5 NO CARD -.- -- ------ ------
6 NO CARD -.- -- ------ ------
7 NO CARD -.- -- ------ ------
8 DTRU-T1 1.1 00 ------ ------

If you are a dealer contact NEC tech support from customer site and have your lap top with you. They will have you collect system data and email to one of their engineers. Keep in mind you might have to leave your lap top over night This data will pin point what is causing the problem. They will also ask to have the receptionist log times of the drop calls.

Dan S

to follow this up, I finally got in contact with NEC, and was able to get them a trace between the T1 card and the CPU. apparently the phone company had been flashing the line (A&B bits going low then high) after sending sending ANI and DNIS, which wasn't being handled properly by the DS2000. NEC acknowledged the problem and plans to fix it in a subsequent software release.

on the other side of the connection, a switch tech at time warner figured out that we were the only connection going through a DACS. after removing us from the DACS and moving us to a straight cross-connect to the mothership DMS-500, the problem went away, which indicates that the DACS was corrupting the A&B signalling somehow.

so a little bit of gunk on both sides...

Thanks for the update