sundance-communications.com/forum Forums TDM Business Telephone Systems Mitel Telephones & Systems DS1 card on 200ML questions (Possibly a stupid one)

I have a customer with a Frac T1 service with 7 voice channels. One of the channels has all kinds of static but Telco has tested everything and I don't have a spare DS1 card to swap to see if it's the card and the customer doesn't really want to spend the money for a card if I'm not 99.9% sure the card is the problem.

Here's the question(s)...

Can I program any channel on the T1 in form 15 as long as I have seven programmed or am I right in assuming that since the telco is giving me 7 channels, they are channels 1-7 and if I program 1-5, 10 & 12 for instance, the customer will only be able to make and receive calls on channels 1-5.

Next question is I have a CSU ACE which the telco suggested could be the problem but my thought is if it's bad all channels would be bad not just one.

As far as I know you can only program the channels as telco delivers them.

The ace could be the problem but in my experience bad channels on a t-1 are telco- are you converting with the ace? can you bypass the csu?

The channels are all one to one. Your first is the carrier's first.
I would doubt the CSU is bad, because as you said, they usually effect the whole circuit, not individual trunks.

In theory, once the signal goes through the DS1 card's CODEC application, it should be "static-proof" (i.e. all signals are either a one or a zero, and static gets lost because it's neither one).

So the problem would have to be between the user device and the DS1 card, or else between the other end and the remote CSU.

Is the static heard both directions?
Have you tried exchanging the DS1 card for a known-good?
Have you tried moving the DS1 card on the backplane? (i.e from slot 5 to 6 or vice versa)

(Remember, of course, that a DS-1 is a high-powered card and is NOT repeat NOT hot-swappable.)

Is it always the same extension that reports static on the T-1? Is it always extensions on the same ONS/DNIC card?

If it's always the same channel, is it practical to isolate the affected channel in its own trunk group?

Been down this road more than once. The static is coming from the TELCO. Remember, in the C.O they break out in a channel bank. AND SOMETIMES they go through 1 or more intermediate points where they are broken down to audio in one channel bank and then put through another channel bank to a different span. Just because they come into the building on the same span, doesn't mean they got all the way there on the same span! Had a span in Texas that had various problems on various channels. The Telco tech that finally got to the motel had a complete circuit drawing. What a mess. The channels all broke down to audio at least twice on the way from the C. O. to the Motel. And they used at least 3 different paths to get to the final span into the motel. Problems were mostly dialing permission variations, but 2 channels had mild static and 1 had NO AUDIO at all. I finally got action when I itemized the specific problem(s) with EACH channel. The first 2 tries were "Channels have screwed up dialing permission and intermittent static". Of course they checked the first channel and it was fine.

I agree that it is most likely the Telco. Have they checked it all the way to the source or are they just checking the channels from the T1 transmission point at the CO to the NID at the customer? You can busy out the channel until they get it fixed. Unless you are converting the carrier signal (ESF/B8ZS to D4/AMI) with the CSU you could bypass it and see if that works. Most problem with the DS1 effects all channels.

Thanks all, I currently have the affected channel busied out and no other issues were found. Telco says they have "never" just had a channel affected when they had problems. I bypassed the CSU and still same issue. Have not had a chance to change slots on DS1 yet since this will require significant programming changes and customer didn't want to be down that long during normal business hours. CSU isn't converting at all it's D4/AMI.