Hi - I had a client recently move their asterisk system (asterisk 1.4.26, dahdi 2.2.0.1, aex800 w/vpm module) to a "new" location, a building that's nearly 150 years old. I was not personally able to go there, but the person who did the move said the building's demarc room was "scary"-- water leaks, jumbled and frayed wiring, and all sorts of other fun.
The echo on their POTS lines has proven to be quite problematic. The hybrids are balanced, txgain and rxgain are optimized individually for all channels, and the vpm module on the card is doing its job. For many calls, this has been effective. Still, echo remains on calls to some destinations, particularly those on the closer exchanges. On calls to one particular number, if I turn the echo canceler off, the echo sounds as loud and clear as if the destination was actually echo(). With the echo canceler on, echo is still very pronounced. The echo tail is clearly longer than 16 ms. I even tried disabling the vpm module (vpmsupport=0 in base.c) and using oslec instead with a setting of echocancel=512. After a long convergence period, oslec seemed to do a slightly better job than the vpm module, but echo was still bad enough to make a conversation nearly impossible. My question for anyone with knowledge on this: would HPEC do a better job than the VPM module (or oslec)? Can HPEC cope with very long echo tails? Thanks, Noah _______________________________________________ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- AstriCon 2009 - October 13 - 15 Phoenix, Arizona Register Now: http://www.astricon.net asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
