Michael The problem lies not with Asterisk or the cards but with the combination of voip and analogue telephony in general. I can guarantee that you will have very similar echo when you connect your Panasonic pbx to the analogue lines. In fact, your echo will most likely be worse. It is just that you do not perceive it as echo because it occurs more or less coincident with the original sound.
However, the propagation delay through the systems that is introduced by Asterisk and voip (by necessity and design) is the culprit, because this adds the delay which causes the echo to become perceptable. You will never get a match good enough to eliminate echo. What you may be able to do is to get a match that is good enough to allow the built-in echo cancellers to be effective. You don't say where you hear the echo - near end or far end? A small diagram of your system posted on your web site, with an indication of who hears the echo and which echo they are hearing would help me (or countless others!) to help you work this out. I am using 2 X100P cards here in the UK connected to extension ports of a Panasonic KXT616 and we get no perceptable echo at all. Good luck! Rgds Tim Robinson -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: 03 November 2004 15:14 To: Asterisk Group Subject: [Asterisk-Users] An anniversary and a lament for FXOs This week marks one year since I first setup an Asterisk server in the hopes of transitioning my home office to a total VoIP system. The process has been an incredible learning experience. I've tried numerous IP hard phones, eventually settling upon the Polycom IP600 as my choice. I've also used multiple ATAs including all the Sipura products. Using Asterisk has been a challenge, a thrill and (when its working) a joy. However, the one thing that I am not satisfied with is the performance of the FXO interfaces that bring in my PSTN lines. I've tried X100p cards but found them horribly unreliable. I presently use Sipura SPA-3000s but they're only marginally better. How is it that my Panasonic 4 line SOHO phone system (KX-TG4000B) can have four stable, reliable FXOs with no echo at all in a device with a total cost of <$500? It seems to me that there ought to be hardware available that behaves just as well, but bridges the PSTN to the SIP/IAX domain? I've read a lot on the list about how difficult designing FXOs can be, but that flies in the face of the fact that every small multi-line phone system has them...and without expection those behave better than the devices I've been able to try with Asterisk. The Sipura SPA-3000 has several settings to adjust for line impedance and inductive/capacitive line loading....lots of settings, but it provides nowhere near the basic performance of one of the lines on the Panasonic KSU. It's simply mind boggling. So, while I've posted with respect to FXOs previously, I must ask again....what FXO interface device can anyone recommend from real experience? Michael P.S. - I even investigated switching my lines to ISDN to get around the need for FXOs, but SBC won't do it where I live. -- Michael Graves [EMAIL PROTECTED] Sr. Product Specialist www.pixelpower.com Pixel Power Inc. [EMAIL PROTECTED] o713-861-4005 o800-905-6412 c713-201-1262 _______________________________________________ Asterisk-Users mailing list [EMAIL PROTECTED] http://lists.digium.com/mailman/listinfo/asterisk-users To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users _______________________________________________ Asterisk-Users mailing list [EMAIL PROTECTED] http://lists.digium.com/mailman/listinfo/asterisk-users To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
