My FXO story was pretty bad until I tried the Sangoma A200d (2 port FXO with DSP echo cancellation on-board).
Until then I spent countless hours trying to get a ‘normal’ sounding conversation over either of two different analog lines that I have.
My wife, the harshest critic of all, was ready to toss me and asterisk out. Now I can actually get through a day (and counting) without hearing about how the new phone system I put in our house ( … yeah, no one out there can relate to this …) totally made her life miserable.
Given the premium cost for this board I’m sure plenty of folks might toss the Mrs. instead – but it is a miracle worker as far as my marriage and I are concerned.
The problem was ECHO that wouldn’t die no matter how hard I tried to tweak levels and/or use different s/w echo cancellation algos.
Prior to Sangoma I tried/used:
clone X100p
Sipura SPA-3000
Digium TDM400
It would seem that some folks definitely have been graced by the echo gods (and are blissfully unaware of just how vexing it can be) while others seem to have this nagging problem.
My POTS lines are delivered by two different technologies … one is via a cable modem (Motorola product) and the other is a good-old-fashioned POTS line from the local telco, Verizon.
Both lines are fine when used as plain old analog lines (i.e. no asterisk) but each had their own quirks when used with asterisk.
The cable modem line was always less of a problem. The other line was pretty far from the CO (I’m told it’s over 18,000 feet) and there is a noticably lower volume on that line – but it was horrible on local calls and even worse (!) when making long distance calls (via asterisk).
All of my house phones are analog with Sipura SPA-2000 ATAs.
(Maybe someone out there with years of experience will tell me what I was doing wrong – but I was at my wits end and really needed to keep the analog line/phone situation as it was, albeit with usable quality)
Sangoma card was like some magic (expensive) pill that has -cured- the echo!
Truth be told, the first card I received had some weird problem (that Sangoma diagnosed to be) in the dsp daughterboard. They RMA’d it and sent me out a replacement lickety-split.
I haven’t had the card more than a week yet but so far so good.