Echo - Alog Trunks 1

[VoIPP]

Ip Phones alog trunks some brief echo at the start of the call.

9.0SP1 and 9608 phones.

Any new tricks with 9.0 to clear up the echo? Turning off AGC at the phone is what I hear works most of the time.

Thanks.

 

[Westi]

AGC is what I do automatically with analog lines and actually I have had that only cause problems rather than solve any.

Impedance matching is also a must on the lines and measure the line for the mA value it gives you when you just put the amp meter in.
Some lines are just a problem when they are too hot and above 35mA I put resistors into the line. 2 600 Ohm resistors are what I usually put in sometimes 4 but always the same amount on Tip and Ring.



Joe W.

TeleTechs.ca
FHandw, ACSS (SME), ACIS (SME)


“This is the end of the world, make sure to buy your T-shirt before it is too late"
Original expression of my daughter

 

[stivtaber]

When troubleshooting a similar issue Avaya indicated that idle loop current outside of 23-35mA doesnt meet their spec. Sure enough the trunks we were working with were hot, over 40mA idle loop. Resistors fixed the issue.



Stiv Taber
Certified in Convergent Network Technologies
APSS - SME Communications
PA - Implement IPO Professional Edition

 

[DigitalG]

how many watts for the resistor ? 1/4 ?

if it ain't broke don't fix it!

 

[VoIPP]

Westi,

Why two resistors? Wouldn't one resister (at twice the ohms) on either T or R accomplish the same thing?

 

[mforrence]

@VoIPP - resistors on tip and ring needs to be the same. Mike Sandman (

http://www.sandman.com)

also sells a loop current regulator that, while costing much more than a couple of resistors, does a nice job.

 

[azrael2000]

Another thing to try is going to the analog lines, and then run the impedance test.

That might help.

Having an issue here too and I just tried that... will be calling the user to see if it helped.

Regards

 

[Bas1234]

Have a look here;

https://support.avaya.com/ext/index?page=content&id=SOLN243273&group=UG_ENTITLED_CUSTOMER

___________________________________________
It works! Now if only I could remember what I did...

Dain Bramaged (Avaya Search tool

http://tinyurl.com/bas1234

)
______________________________________

 

[cmnstr]

I have had this issue on every ATM4 v2 card installed. Turning off Echo Cancellation and Echo Reduction on each trunk has resolved the problem every time. I don't even test the lines any longer. I just turn those off during staging.

 

[teletomi]

Hi westi..How do you place your two or four 600 Ohms to your tip and ring..???Are the two resistors connected to tip and ring each in series,or are the four resistors, two resistors connected on tip and ring each..??or are both set up in parallel connection..

 

[VoIPP]

Resistors in Parallel TotalR = 1 / (1/R1) + (1/R2) + (1/R3).... (1/Rn)
Resistors in Series TotalR = R1 + R2 + ... Rn

So the resistance of 2 600ohm resistors in series is 1200ohms.

The resistance of 2 600ohm resistors in parallel is 300ohms.

I am guessing a second resistor is added in parallel to add more resistance but you can add them in parallel if you need less.

In this install I found that the lines were running at 47mA. I installed one 470ohm resistor each on T/R and that brought it down to 27mA. Didn't have any echo after that.

 

[VoIPP]

I am guessing a second resistor is added in parallel to add more resistance but you can add them in parallel if you need less.

should be

I am guessing a second resistor is added in (series) to add more resistance but you can add them in parallel if you need less.