John Novack wrote: > Since the OP said the noise was on FXS ports, Jorge's answer isn't > relevant. > After listening to a wav file of the noise, it sounds to my old ears > like a background hiss or so called "comfort" noise, except for a couple > of short pops which I assume to be an open microphone.
Yeah, that's correct. Sometimes the background noise warbles a bit. This is why I am wondering about ground. The background noise is too inconsistent to my virgin ears to feel like deliberate comfort noise. I wasn't aware that these modules were supposed to generate that kind of comfort noise. Usually sidetone is enough to make the set feel live to the user. > Assuming this isn't generated by the POTS set connected to the port, I > guess you'll have to dig into the configuration. > Some POTS sets generate a similar though more erratic noise, caused by > carbon transmitters and defective varistors in the network, but that is > ancient history. > More modern POTS sets with electret transmitters could certainly > generate a similar noise. > I am assuming that several different sets have been tried with similar > results. I have tried: a cheap AT&T set; a refurbished Northern Telecom "Symphony"; a classic ITT Touch Tone set All of them sound great when connected directly to the PSTN (okay, maybe the cheap AT&T set sounds a bit tinny), so I'm confident the sound is not coming from the sets themselves. > My experience with the Sangoma A200, and in fact Digium 400 and Adtran > channel bank FXS circuits all are very quiet, so this is a bit of a puzzle. Well, that's reassuring, because it means a solution must exist. I don't know what configuration changes I would make to solve this. My gut feeling is that it's an electrical problem somewhere within the system, but perhaps I'm reaching for that too soon; in any case, I wouldn't know where to start even if we accept that it is an electrical problem. Is a dirty ground not a possibility? Is there a way to test this card in another server without having to install Asterisk on it? I want to see if the noise is coming off the PCI bus. -Stephen- _______________________________________________ --Bandwidth and Colocation provided by Easynews.com -- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
