HI Keith, We have worked with both software echo cards (Digium) as well as hardware echo cards (Sangoma)
I did a little research on the ChinaRoby FXO modules and I suspect they are the Echo issue you are having. The Digiumrequired us to purchase a special echo cancellation software that cleared up the problem. The Sangoma came perfect right out of the box, doing it again, I would definitely always go with the Hardware echo cancelling. Question: Have you run FXOTune? This what we had to finally use to solve our issues Here is what I have in my notes for Echo Tuning using fxotune: service asterisk stop fxotune -i 25 > /home/test fxotune -s /etc/init.d/zaptel restart fxotune -s /etc/init.d/asterisk start Below is the link to the Digium echo cancelling software that we added as well: http://store.digium.com/productview.php?product_code=HPECLIC Hopefully this helps Keith, -Bill Ensley www.bearprinting.com Question >> I expect Wes and Aaron will have useful opinions, but there might >> be other lurking Asterisk PBX users on the list. I'm close to >> finished configuring a small-but-complicated Asterisk setup for >> my wife's office - a few logic/dialplan/workflow tweaks remain. >> >> The system connects three Cisco 7940/60g phones to three Centurylink >> POTs lines. I believe we are about three miles from the CO, but >> there is likely a nearby remote switch, because the fourth DSL/FAX >> line is running 7Mbps, and the loop must be short for that. We >> are in a commercial office building and don't get to tweak on >> the wiring onwards from jacks in the office. >> >> === The biggest remaining issue is echo. === >> >> The echo may be due to the Cisco handsets, which are functionally >> opaque. The echo on at our end, which sounds like very ringy >> sidetone listening on the handsets, ranges from briefly annoying >> to completely unacceptable. There is no detectable echo on >> either the voicemail or for those calling in. I'm guessing >> there is some second echo cancellation process that I need >> to turn off. >> >> I am running Asterisk 1.8.7.1 - pretty recent, but I am hoping >> to never update it unless a major flaw emerges. The analog >> FXO modules are chinaroby via ebay. >> >> I set /etc/dahdi/system.conf with echocanceller=mg2 on all the >> incoming analog lines. I set /etc/asterisk/chan_dahdi.conf with >> >> echocancel=yes >> echocancelwhenbridged=yes >> echotraining=128 >> rxgain=9.2 >> >> The rxgain was set by calling a 1004Hz 1mW test line in Seattle >> and calibrating with dahdi_monitor for a level of 14500 units. >> I couldn't find a closer test line, and the service techs at >> CenturyLink in Portland don't know what I'm talking about, but >> I assume that with digital trunks connecting these Centurylink >> COs I am getting the same level of signal. 9.2dB seems like a >> lot of receive gain, but it doesn't seem to affect the echo, >> and again, the folks at the other end hear us just fine. >> >> 99% of our calls are to the Portland/Vancouver area, we don't >> need three way calling, and we need to keep POTS/analog for >> reasons I won't dwell on here. If needs be, we can replace >> the Cisco phones, but I am not fond of "buy and try". >> >> Any suggestions? The woman answering the phones is ready >> to kill me, and she probably knows how to do that in a >> forensically undetectable way. I wouldn't want to subject >> her to the remorse, my wife to the burial expense, and you >> folks to the subsequent peaceful/boring mailing list. :-) >> >> Keith >> >> -- >> Keith Lofstrom [email protected] Voice (503)-520-1993 >> KLIC --- Keith Lofstrom Integrated Circuits --- "Your Ideas in Silicon" >> Design Contracting in Bipolar and CMOS - Analog, Digital, and Scan ICs >> _______________________________________________ >> PLUG mailing list >> [email protected] >> http://lists.pdxlinux.org/mailman/listinfo/plug >> _______________________________________________ PLUG mailing list [email protected] http://lists.pdxlinux.org/mailman/listinfo/plug
