We have an SL1100 with a PRI circuit from Optimum (cable company). Incoming and outgoing calls on digital phones are fine. Outgoing calls using an analog station result in massive echo on the called party side (recipient). The echo occurs for all outside parties. No echo on the inside party. No echo on internal calls.

We have adjusted 10-03 SLI DB Trans and Rec and 14-01 Trunk settings transmit and receive. We also adjusted the cable length in 10-03-06 to Level 1. No improvement really only slight improvement. NTAC says the PRI is coming in TOO HOT from the telco. The telco is using a Edgewater 4550 unit to deliver the PRI but getting the telco to comprehend the problem is a bit difficult .

NEC Ntac suggests using an CSU/DSU in between the Telco and the NEC. I have Adtran ACE but I always thought they would boost the T1 signal and we want to drop the signal by -7.5db.

Am I correct about the CSU (useless)? What are you other suggestions?

This has been an ongoing issue but we always suspected an old Polycom conf rm phone was the issue but that has been replaced.

You did not mention inbound calls to a analog device, any difference?

Same issue. Echo on the far end. 10-03 brings it down but still very obvious and disorienting. Different SLI card in expansion cabinet same problem.

What kind of analog phone?

What level did you set 14-01-02 and 14-01-03 to?

Putting a CSU can't hurt but I am dubious. It should regulate it and give you control of the output. I would question the analog phone quality and that is why I asked. Does this happen on a good buttset? Have you tried another type analog phone?

I've used a good quality harris ts21, polycom soundstation and an at&t feature phone 864. All same result. The CSU I used was Adtran ACE which is a pretty basic unit. NTAC did not suggest a particular make/model of csu.

I don't know if I can get into the Edgewater 4550 or not. I've found manuals for it and can see there is a T1 configuration screen. But it isn't mine and risky perhaps.

I got the customer a pots line so they can use their new Polycom but I am rather disappointed the sl1100 has this problem and I don't know if it has happened to other people with PRI on the SL1100.

What level did you set 14-01-02 and 14-01-03 to?

I recalled we set 14-01 -02 and -03 to -3.5 and then -7.5 with no change. Then put them all back to default. I did this with NTAC on the line. We did not reboot the KSU until we adjusted 10-03-06 to level 1. Basically they say it's the telco. But the problem only occurs on SLI ports, not digital.