I've been beating my head on a wall on this one and wanted to see if anyone else has had the same issue. I've contacted Sangoma, but haven't gotten very far. My issue is that I'm getting a noise that I could only describe as a hissing and popping on FXS ports. FXO ports have zero background noise. Here are a few other things:

• I've tried multiple A400s - purchased at different times and probably from different manufacturing runs.
• I've tried different FXS modules.
• I've tried different servers (from our standard white box to a Dell PE 2950).
• I've tested the port on the backplane by dropping an FXO module in - the port is fine.
• Sometimes, only 1 of the 2 channels on the card is noisy
• Only unloading wanpipe will make the sound go away (I assume it removes battery from the line also)
• It's not environmental since I've tried this in multiple environments. I've even taken the stock cable and connected it to a butt set - and STILL get noise

HELP!

Hmmmm... Stay away from Dell servers. They like to burn up telco cards (doesn't matter who's, they just like to burn 'em up).

Is this an echo-can or non-echo-can card? I've ran into something similar to this on echo-can cards but that had to do with a dated firmware. Also had this happen through noisy/bad ground to the chassis.

Also got a few other questions: What version of firmware are you running on the card? What version of Asterisk? What flavor of Linux? What linux Kernel? What Zaptel version? What wanpipe version? Is this trixbox? What are you doing when it snap crackles and pops? If a train leaves boston at 5pm going east as 30mph, and another train leaves new york at 6pm going 40 mph on the same line, how long till they collide?

Ok, maybe that last one was just for fun.

And just to make sure we are using the term FXO and FXS properly, the FXS Modules are what you are attaching your phones to correct? And the FXO modules are what you are connecting to the POTS lines from the telco?

Ok... Here is a bit more info. First, we don't normally use Dell servers - they were part of a state project - we just had one available to test with. Our normal servers are roughly spec'd as Athlon X2 4200+, 1GB RAM, Gigabyte mobo (model varies).

We're using the latest firmware on all the cards - we've also tested the last revision (what was originally loaded), but the updates in the last revision were only for EC cards, which ours aren't.

Here are the versions of software we're running:

• Asterisk: 1.4.5
• Zaptel: 1.4.7.1
• Wanpipe: 3.2.1

We're not doing Trixbox at all. These are Debian/Ubuntu systems. I've seen the issue on Debian Sarge (2.6.8-3) and Ubuntu Feisty (2.6.20-16).

As far as what triggers it - nothing. I can even hear it when there is dialtone on the line. I don't think it's Asterisk since the sound is still there when Asterisk is unloaded (just no dialtone of course). The sound only stops when I unload wanpipe.

Yup, I realize the difference between FXS and FXO. I'm using a phone or butt set on the FXS side for testing. When I said it was clear with the FXO, I had the card connected to an analog line on a Comdial switch and dialed into it from the Comdial side to a "silent" extension (just answered and wait(30)).

I'd recommend upgrading to Wanpipe 3.2.3, and Asterisk 1.4.17+. The version of wanpipe (if I remember correctly) had some audio issues on the A400's. Any version of Asterisk 1.4 before 1.4.17 is a crap shoot. Everything since then has been very stable. Just for fun you can issue the command "wanrouter hwprobe" and in the output the V=10 line will tell you what version it is, or in this case, version 10. If you aren't using version 11 then try upgrading firmware.

I would try compiling wanpipe 3.2.4 first. If this fixes the crackle then you had some sort of driver issue. Have you tried reversing the modules on the card? I.E. isntead of module one being FXO, having module 1 be FXS? I think you said you did but I just wanted to double check. Also, are you using daughter cards, and is the crackle happening on the daughter cards or the main card? Do all the FXS modules have the issue or only certain lines that get plugged into the modules?

I have had issues with an out-of-spec POTS line getting demodulated in weird ways and causing issues, but that wouldn't really apply here.

I would also recommend you update Asterisk. The early version of 1.4 were about as stable as a match in a hurricane. While this might not be your noise issue it will certainly be screwing something else up eventually. Your mileage may vary.

Yup.. I've swapped the modules (bad FXS with "good" FXO to see if the slot was bad). I'm not using daughter cards on any of my A400s. I didn't realize there was a wanpipe update, but I'll install it.

BTW, I'm pretty surprised about the stability comment. We've been running the same version on everywhere on our network (the machines with the A400s are IAX trunked to a central location), and even at our central location, things have been rock solid.. I'll put upgrading on my list, however.

Well stable is a relative term. To put some hard numbers behind it I install predictive dialers that use Asterisk. 1.4.17+ can finally handle the load I need it to, which is around 6-80K dials per day across 4 T1's. The older 1.2 version of Asterisk is still more stable but not by much (90-110K/dials/day). Granted this scale might be completely different then what you use asterisk for but it still relates to overall reliability and stability.

The version of Asterisk you are running would crash in 2 minutes or less when I tried to do a simulated call volume.

No dice.. I upgraded wanpipe last night and no change. I've got it on 3.2.4 now. I also upgraded this card to FW v11.

I'll upgrade Asterisk later. I really don't think its Asterisk though..

Just for fun, try rebooting. See if the static goes away. Earlier revision cards seemed to have an issue that was modified on later revisions.

I've rebooted the server before and it doesn't seem to matter. BTW, both of these cards are less than a year old. One is just a few weeks old (I think it came direct from Sangoma - it had customs paperwork).

Interesting... You've tried calling Sangoma and dont get any response? The few times i've called them they support was top notch. Level 2 is an engineer. Level 1 is the receptionist who ask's if you did some basic things. Try calling them again and opening a ticket with them.

I have... Still waiting for a card to make its way back to them.. Just was wondering if anyone else had experienced any issues.

Only experience I have had with Noise and POTS lines was on a sangoma FXO card where the line was coming in too hot and the signal would get demodulated funny. Paid someone to hook up to the line and balance it before going into the server and problem went away. Doesn't really apply to your FXS issue tho.