BCM 50 echo 1

[stevomorrison]

I have a BCM 50 3.0 fully patched with echo issues. The system consists of 1 BCM 50 3.0 with Digital phones at the main site and 5 locations with roughly 4 phones per site all connecting over VPN. The echo only happens when using the analog lines. I know you can tune the lines when you have echo with voip using the long/short haul and impedence. Does anyone know what has to be done and how to know which distance long/short/medium to use.

 

[oldestgeek]

Changing the CO loop length to short will add padding to the circuit, thereby reducing the amount of signal transmitted and also the amount reflected back as echo. You can also purchase in-line pads if the line settings don't do the trick. Keep in mind that the volume will be decreased when using the short setting or adding pads and externally transferred calls and external conferences will have very reduced volume. Good luck - that can be a tough one to fix.

 

[endlesswinter]

my personal experiance is analog lines and ip dont mix well.

 

[telcodog]

There's a really good document you can get from Nortel's website called Managing Echo on BCM50 and SRG Installations that deals with exactly the problem you're describing.

If you can't download it, let me know and I'll FTP it to you somewhere.

 

[stevomorrison]

Yeah I seen that doc telcodog. I am just not sure what to set. Not sure between short, medium, and long, and do i have to change the impedance to 900. If i make these changes do i need to do a restart and then go on each trunk and press the line tuning digit 1.

 

[foneman1]

Does it do it when using digital sets? I had the same problem with a customer that had digital sets only with analog trunks, some one on this site told me to reboot the system and let the system sit idle for a while so it can fine tone the lines. I did that and it cleared the problem. I tried to fined the post but I could not fined it. Good luck.

 

[oldestgeek]

Stevo, the default loop length setting is medium. If you change it to long, you'll be removing padding, thereby increasing current and volume and probably making the echo worse. Set the loop length to short and reboot. I don't think you'll need to press any digits. Also, the 900 ohm impedence setting will most likely do more harm than good as most telcos tune their lines to 600 ohms. If you still have echo after setting the loop lenght to short and rebooting, try searching the web for echo reducing adaptors that will allow you to change the impedence and current of the line to match the trunk mbm.

 

[stevomorrison]

Thanks Oldestgeek. I will try changing it to short and doing a reboot first.

 

[CharlesBr]

Thanks guys, we just fixed a very similar problem with the "short co and reboot" advice!

Main site: bcm 50 3.0 with december 2008 SU, digital and ip phones, analog trunks
Remote site: ip phones

ip-ip, ip-digital, no problem
ip-analog lines, "echo" as in you heard what you just said.

we tried changing the codec to g-729, and we also tried to reduce the jitter buffer, to no avail. It worked only after the reboot though, so it might be related to any of the 3 changes... does a codec change needs a reboot?

 

[oldestgeek]

A codec change does not need a reboot but the loop length change does not take effect until a reboot or a disable/enable of the module.