Conference Feedback / Poor Speakerphone Function

[roberth5]

For some time now I have had a feedback problem on conference calls and the speakerphone function has been poor on a (former Partner II, now ACS) system I installed in a real estate office in the Metro Detroit area. I up-graded from a Partner II to an ACS R5, and the problem persists.

Whenever a conference call is set up on two outside Telco lines, the pots lines have a loud squeal on them (feedback).

I have read a few threads here on Tek Tips that people have used attenuators to resolve the problem. I have 9 pots lines on this system, I would need about $400.00 worth of attenuators to resolve the problem. Or just install another (different brand) phone system, as only the Partner system seems to suffer this conference feedback problem.

Does anybody have any other solutions or recommendations on another brand of phone system that will not feedback on the conference function?

I have had SBC & LDMI on site, they have firmly stated to the Customer that the problem is in the phone system and not the Telco pots lines/systems.

Anybody have any additional ideas on how to resolve such an issue?

Robert

 

[skip555]

check out this tech bulliten on loop current

I just ordered some yseterday and was reading this when you mentoioned the squel it
clicked

http://www.sandman.com/loopcur.html

his llop current regulators run about 40.00 per line

I would give it a try if it where me

 

[1043]

What type speakerphone are you using?

 

[roberth5]

Partner 18D Phone, ACS Processor, 2ea. 206 and 1ea. 400.

I have not measured the loop current yet. I will break out the Fluke on next visit. I did place two (2) 100 ohm resistors in series with the Pots line, no help.

However, if I placed a 100-ohm ACROSS the line (momentarily), feedback ceased (momentarily). Placing such a low resistance on the line will probably not allow connection to drop. Telco will assume "off hook" condition exist while 100-ohm resistor is across the circuit (I would expect).

I tried calling Avaya, however, no luck at finding a good support phone number. I emailed question to Avaya and Metroline direct, no response yet.

 

[comdata]

The circuit you are trying to emulate is a 400 ohm resistor in series with a 15mf capacitor placed across the T&R, which was encapsulated in what was called a 185A network. Worked quite well in some paging systems that produced loud pops due to improper timing of the switchook hangup.