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Posted By: Keighlar Digital lines to Analog DTMF issues - 11/26/08 10:47 AM
We just installed an NEC DSX 80 into an establishment with TechValley digital lines handed off to analog signaling.

Issue: Sporadically the voicemail (intramail) will not recognize DTMF and goes into a constant loop. I cannot reproduce this on a consistent basis.

Attempted Solution: Turned up the receive gain on all trunks to +3.0 dB and I'm doing the waiting game.

Are there any specific things I need to ask the dial tone provider (TechValley) to adjust? Has anyone had this issue with TechValley in the past?

NOTE: This is NOT a phone system equipment issue. The system works consistently off the customer site fed by pots lines.

Any insight would be greatly appreciated. Customer is IRATE.
Posted By: Silversam Re: Digital lines to Analog DTMF issues - 11/26/08 05:10 PM
Keighlar -

I'm with you on trying the boosted gain as a first shot. I had trouble once with an E&M tie line to Paris. nothing worked till I cranked the gain way up - then all the problems went away.

What format are these digital lines? ISDN? Something else? How is the handoff to analog signaling being accomplished?

Do you have a DTMF tester you can put across one of the VM lines? Even if you can't duplicate the problem consistently, if you can get it to happen while you're monitoring the circuit, that'll be a big help.

Sam
Posted By: boots921 Re: Digital lines to Analog DTMF issues - 11/26/08 06:44 PM
Are the digital lines in a hunt group? This reminds me of an issue we had several months ago. 2 out of 10 of our E&M Tie Lines connecting to a Meridian1 are set up to collect DP and they suddenly stopped accepting accepting digits one day. Turns out, the meridian techs changed the address signaling to DTMF on these 2 tie-lines so our Harris switch would just timeout after 30 seconds. If TechValley has DP address signaling enabled on some of the trunks while your VM is looking for DTMF? Like Sam said, next time the problem occurs, Bridge the line and take measurements
Posted By: Keighlar Re: Digital lines to Analog DTMF issues - 11/28/08 06:03 AM
Sam,

I'll have to get the specifics on these lines. I'll do that and post back.

boots921,

They are in a hunt, but in testing the lines I isolated each of them and made repeated test calls to each line to eliminate the possibility that one or more of them was misconfigured. In 80 calls I was unable to get a single failure; however, the dispatcher at our office did make one call that duplicated the customer's complaint. It has occurred with both cell phones and land lines.

Thank you both for your input.
Posted By: IPKII Re: Digital lines to Analog DTMF issues - 11/28/08 07:22 AM
NEC had a similar issue on the IPK II platform w/ the InMail. They had designed a software patch to address it in the InMail. Perhaps the NTAC side that supports the DSX has a similar fix?
Posted By: IPKII Re: Digital lines to Analog DTMF issues - 11/28/08 07:44 AM
Perhaps this thread should be moved to the NEC catagory?
Posted By: Keighlar Re: Digital lines to Analog DTMF issues - 11/28/08 08:21 AM
I put it here simply because I am certain it is not the NEC equipment and it has something to do with the telephone service. That being said, if it would make a better fit in NEC, I'll ask to have it moved. I talked to NEC tech support already and there is no patch.

I'm waiting to hear back from TechValley with the specs on the lines.
Posted By: Keighlar Re: Digital lines to Analog DTMF issues - 12/03/08 10:22 AM
Update: I still haven't heard back from Tech Valley, but in the meantime I adjusted the Receive Gain to +3 and we have not had any additional complaints so far.

Keeping my fingers crossed...
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