atcomsystems.ca/forum Forums TDM Business Telephone Systems Inter-Tel Telephones & Systems Sidetone

We just installed 5- 8622 IP phones on Ver 9.0.
On an intercom call, audio great. On a CO (outside) call, we hear ourselves back about 1/5 of a second later. CO connection by copper (approx 10 feet) to a fractional T1 as individual trunks, loop start. Tried all diff settings on IP phone voice setup 8k,64k audio, etc., but this doesn't seem to be where the problem is. Thanks for your help.

this sounds like a classic case of VoIP echo. It occurs when you mix analog and digital signals (aka hybrid). There may be no fix for this. You can trouble shoot with Telco but they will turn a deaf ear. Is there a chance you can leave the T1 as digital and not use the multiplexer to convert them to copper on the PBX? This is just a 15,000 ft diagnosis of course.

I'm not sure. We took the t1 as analog for 2 reasons, first we had the analog CO cards already installed, and second, it is a half data (streaming video, half dialtone T1 -12 lines-. The original drive for the T1 was to get ANI from an 800 number. (local telco wont pass ANI on a pots CO line.)

I'm Sorry, I misspoke- the pots CO line will pass local ANI, just not the ANI from our 800 carrier. Also, we are using the data side of the T1 for our IP phones as well as the streaming video.

I could recommend a couple of tweaks you can do in DB Studio (change hybrid balance to short on the trunks or backplane attenuation to -3) but i think you would be chasing your tail. my 2 cents only, and you may want to get a reseller to come out and confirm, but, the reflection you hear is most likely caused by analog meeting digital. eliminate that may, just may, root out your problem.

Thanks everyone, I put in a trouble ticket, and Inter-tel will be out tomorrow. Hope they don't shrug their shoulders and say that we spent 10K with them for nothing. I saw the long and short setting, but didn't know if I could hurt something by changing it.