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Has anyone found a way to make the esi system resync after if loses the D- channel? I have yet another client who has developed this issue. Thanks

Never had that problem - we have many ESI's with PRI's installed.

Why would it lose the D Channel to begin with?

That is typically a carrier issue unless you have a faulty card.

Please provide some more specifics and check your fault log.

The D-channel drops usually from the carrier side, when this happens esi has no way of reestablishing the connection. The only way I have to correct this is to reboot or disconnect the PRI and reconnect. It seems to happen most with poor copper coming in, but it has been happening enough with different clients/carriers that I would like another solution. For instance putting an ACE in between. BTW the esi never shows a fault, in fact you can still receive calls, you just can't make them.

I have had similar problems with a couple of systems recently that I went around and around with the carriers. In both cases it turned out to be just a symptom of a hard drive on it's way out. On both after replacing the hard drive there have been no further problems. The hard drives sometimes go in small increments. Hard drives are the Achilles Heel on those older ESI's

This is not a hardrive issue. I have had this problem on 50's 600's 200's like I said it is normally a carrier issue, but if there is a way to prevent this, or correct it I would add it to every system that has a PRI. Apparently Fort Wayne has some pretty crappy copper in it. Thanks

I've seen exactly what you have.....although it seems to be way better with the newer systems...........back in my early ESI days i often thought about an Adtran in between.

You should always has a CSU in between the carrier and the CPE. This gives you a test point and a loopback facility for you and the carrier.

I agree about the csu, but all my carriers have adtrans in between, and I have the csu emulation turned on just in case. That is except for verizon and we do use a hardware CSU in those cases.

I was a trouble shooter for a clec running a lucent 5ess.Can't tell you how many key,cbx,pbx systems I ran into who had two csu"s running back to back having pri issues. By having the vendor to disable his onboard csu we cured a host of problems.Might be worth a try

If you have a T1/PRI delivered by a carrier it should be at 0dB loss to the dmarc then make sure your CSU has its LBO set to 0dB as well.

As long as all settings on the CSU's and D channel are correct 2 CSU's should work perfectly well together