atcomsystems.ca/forum Forums General General Telephone & Systems Information phone system for polycom 550s

i wanted to check if anyone could recommend a phone system that is compatible with polycom 550s and 330s. my company bought an asterisk based system and we have been having issues with echo and noise on outgoing/incoming calls. we use voip internally and the sound quality is pristine but our outbound calls go over a PRI and the sound quality (echo, static, hissing, etc) is not at all what we were expecting.

we went with a voip system to benefit from networking our 5 branches together and they ability to do screen pops from our crm application.

the vendor is willing to take back the pbx but we would be stuck with the phones. can someone recommend another non-asterisk based phone system that will work with the polycom sip phones.

Iwatsu's ECS with SIP licenses will allow you to reuse the polycom phones. Features are limited because they are 3rd party phones, but you can make, answer, transfer, place on hold, etc..calls.

Their IP campus networking would tie the 5 branches together.

They should work fine on most any platform supporting SIP. Of course you will only get the SIP features though. For example, if you put it on an Allworx they would work, but they would not have all of the Allworx features like an Allworx IP telephone would have.

Steve

Hold on here just a min. You say the internal is pristine and the problem only comes on external call. Are you sure it's not your bandwidth? Because if it is you are going to have the same problem with a diff system as well.

You may want to send Kumba (moderator) here a PM. I sent one to him about your question. He is an Asterisk programmer. He may PM you.

It seems to me, that your system is not set up right for the PRIs. Just a guess.

Hmmm.

Static and Hissing on a PRI? Sounds like either some bad endpoints or you aren't really using a PRI.

If you actually are using a PRI then I would do two things:

1) Call the carrier and have them do intrusive testing to the smartjack to see if there are any errors between them and you. If your PBX vendor is knowledgeable enough it would be good to have them coordinate with the carrier to loop through to the PBX for a fully encompassing test.

2) Have the company that is willing to take the system back program you a whole new second system and see if that fixed the problem. If the T1/PRI card in the system is bad then this is the easiest way to see. There is also the possibility that the T1/PRI card they are using (as far as the manufacturer) is junk. I recommend Sangoma almost always.

The problems you are describing are usually not indicative of a T1/PRI failure. Bouncing Spans, dropped calls, stuttering audio are more of what I would expect to see with a bad T1 circuit. It is possible that there could be a bad DSP at the carrier's side. If you let the carrier know your symptoms they will be better inclined to look in the right places.

With the combination of symptoms you describe I would say you are actually using POTS lines that are going into a card without Echo Cancellation or proper line conditioning (Impedence, agc, etc).

My next question is what is the PSTN Interface? Is it an actual hardware card in the server or some kind of media gateway? Can you tell me what model #'s they have?

thanks for all your replies!

kumba, we are using a TE122 digium card with echo canceler on a switchvox system. we've actually switched out the hardware a couple of time without any improvement. now our installer has temporarily given us an asterisk server with a dual span t1 card to act as a SIP gateway which has improved the sound quality a bit but this has caused some other issues with the SV gui and DTMF. SV tech support actually updated some of their software last week which i am going to be testing tomorrow night. hopefully this will help with some of these issues.

i've also been in touch with the trixbox people and they are willing to send me a server with a sangoma card to test with. i will probably take them up on their offer but i've read mixed reviews about trixbox pro/pbxtra so i'm a little hesitant. i am willing to look at other systems but they would have to have the screen pop capability and obviously work with the polycom phones.

we're also working with the telco because the circuit has bounced a few times in the couple of months that it has been installed. they did intrusive testing about 5 or 6 times and did not notice any issues. finally after multiple complaints they sent someone on site last friday and saw some errors. they are now running a new pair so this should at least help with the bouncing circuit.

any other suggestions or recommendations would be greatly appreciated.

Ok, there is no guarantee that the TE122 has echo cancellation or not. Fortunately On digium cards it is fairly easy to tell if it does. Open up the case, look at the card, and see if it has a small purplish/blue daughter card on the main part of the card. If it does then that is the echo cancellation.

Other then that it sounds like you may potentially have bad termination at the telco. If the DSP or terminating switch has a problem past the CSU/DSU then it would not show up in testing. The intrusive testing is an interception of the circuit before termination to test the physical line and transmission. If they are running a new pair then you will be getting a new circuit. If it works on the new circuit then it was something associated to the circuit path on the old one.

This is not to common (at least I like to think so) and also a real joy to figure out. I've actually had to generate proof of this by having a server call itself from two paths (one PRI or SIP or whatever to another PRI or SIP or whatever). I would play 1000hz@0db (milliwat) from one direction and then 2500hz@0db from the other direction. Add in some scripted audio analysis and you have all the proof you need. It's pretty hard (or ballsy you could say) if they insist it's your problem when a waveform of a solid tone looks like the stock market graph.

I wont even go into routing issues. That's a whole other ball of wax

Going to this extreme is probably somewhat overkill for your situation though. I would vote you wait till the new circuit is delivered and see how it sounds over that. The one good thing about Verizon in the greater Tampa Bay area is that if they need to move wires they build a whole new circuit.

i'm sure that the card has an echo canceler. we've changed it three times already, all with an echo canceler but the first version was pci-e. we're now using a pci version.

yeah, i really hope that the new pair solves the problem but i'm really skeptical. we've tried so many things to fix the issue that i'm beginning to think that there is no solution.

one of the most annoying things that happen is with background noise during a call. when i or someone else speaks there is no background noise at all but once the speaking stops the noise starts again. the transition from local speaker to remote speaker can make the call sound somewhat like a walkie talkie. its difficult to discribe but it is very annoying.

most phone systems will work with the polycom phones, but like stated above you will be limited by the sip protocol

just out of curiosity - what brand was your old phone system ?