Randomly sounds like I'm in a tunnel

My company set up a voip server at a local car dealership, running all their phones. It’s a monster of a server, plenty for the voip. I’m not sure exactly what version is out there but I was curious if anyone had heard of this problem. It only happens on a couple phones, and seems completely random, but all of a sudden in the middle of a call, it sounds like you are in a tunnel. It comes and goes in the middle of calls and we can’t figure out what the hell it is, since it’s so random it seems. First instinct was that the server was choking with a lot of people calling, but it still happens after hours with only 1 or 2 people there. I can probly get some more specific config files and version numbers tomarrow but I just wanted to throw this up and see if anyone else had encountered the same problem. We use the Aastra 480i and some Cisco phones out there. It mainly happens to one desk, which has an aastra phone, but they were saying it happens other places also, so it may be both the cisco and the aastra phones. Any help would be much appreciated.

do you have POTS trunks? if so that is where the problem is…
i had a similar problem with a client using a TDM400… solved it by switching echo canceller to mark2 and enabling aggressive echo cancellation…

I have installed asterisk and Grandstream at a car dealership. the General Manager wants to know if this has been done anywhere else. Kade can you get me a reference on your car dealership and does anyone else know of a dealership that has asterisk installed. Additionally helpful if they have Grandstream installed.

I have been fighting a building struck by lightning and I need to build up their confidence in Asterisk and Grandstream quickly. It took two months to prove to the phone company the back side of a smart jack was flaky. We have been running clean for only a week now and almost all of the random problems have gone away

One of their last complaints is random echo problems. I will try the mark2 and aggressive. Thanks Iron Helix.

actually as fate has it one of the places I had this with was a Grandstream install. Customer was very budget conscious, I would not use GS hardware otherwise. (more expensive IP phones ‘feel’ better, which gives customer better impression of the system, even if it’s just because the handset weighs a few ounces more… besides AAstra phones are easier to deploy)

three incoming POTS lines with decrepid wiring, one * server built out of spare old computer from company owners basement, five Grandstream GXP2000’s. Line had noise right after you take it off hook so it needed a w before dialing (ie exten => NXXXXXX,1,Dial(Zap/g1/w${EXTEN}) ). Also horrible line echo, very transient, would come and go one day to the next. Echotraining on, echocancel on, etc etc etc. aggressive echo cancel made it disappear immediately.

System is not connected to the Internet (no DSL) and has been running wonderfully for almost a year now…

I can’t find where to turn on aggresive echo cancelation. I looked all over in the config files and everywhere I could think of. Thanks for the info guys, I’d love to get this taken care of today.

Oh, you prob wouldnt want to talk to them till we get this echo taken care of, we dont use grandstream, but they seem to be very happy with the whole system other than the echo, after I get that taken care of, I’ll drop you a line here with a way to contact the owner. Thanks

The install in question was an animal hospital, it was a small family-run thing with only a few extensions. I can provide full details but I can’t disclose their info as a reference… sorry :frowning:

As for aggressive echo cancel, its in one of the zaptel source files, IIRC zconfig.h. You need to ensure that the mark2 echo canceller is the only uncommented one, and that aggressive suppressor is also uncommented. You then must recompile and reinstall zaptel for this to work.