We are running asterisk with a single POTS line for local calls and a voip line for long distance. Whenever we receive a call on the POTS line it is more than likely, but not always, going to have significant distracting echo. In addition to that there is occasional heavy crackle or static. I have tried to follow the guidelines at : http://www.voip-info.org/wiki/view/Asterisk+echo+cancellation but it does not seem to have made much difference. Currently we are using a X101P for the POTS line and a TDM401B (TDM400P with one FXS port) for the conventional telephones. From what I have read, it may help to use an FXO port on the TDM400P rather than the X101P for the POTS line. What is the "conventional wisdom" about the echo in this configuration and what causes the crackle and how should I tackle that? I have tried rebooting/power-cycling the machine to reset the hardware but it really hasn't noticeably helped. Is there anything else that I can try? Thanks, Mike
I went through the same thing on my home system a couple months ago, and asked similar questions.. The "conventional wisdom" is that "it depends"... It depends on your local loop length, quality, taps on the line, etc.. It seems that most people who have the sangoma cards with hardware echo cancellation are happy, but I didn't have that kind of money to spend on my home system, so I bought the TDM400 card. In my case, I bought two FXO and one FXS.... Also just "in my case", the difference was huge - All of a sudden my echo problems were gone. So, although I probably would have been better off with the hardware echo, in my particular case, the Digium works great, and did make a huge difference over the voice modem I had been using. Just for comparisons sake, my two FXOs are connected to: 1 Vonage ATA (Motorola), and one Verizon pots line. I am about 2.5 miles from the CO, but I don't know the path that the cable takes, or if there's a SLC somewhere, so I don't know how long the loop is. The line is DSL qualified, so I don't think there's a SLC, but I'm not positive.. Since you've already got the card, you'd probably be able to get the FXO for around $65, right? I'd say that is your best bet, with very little money risked.. Good luck!! -Steve -----Original Message----- From: M.Hockings [mailto:veeshooter@hockings.net] Sent: Saturday, June 17, 2006 1:23 AM To: asterisk-users@lists.digium.com Subject: [Asterisk-Users] Echo and crackle We are running asterisk with a single POTS line for local calls and a voip line for long distance. Whenever we receive a call on the POTS line it is more than likely, but not always, going to have significant distracting echo. In addition to that there is occasional heavy crackle or static. I have tried to follow the guidelines at : http://www.voip-info.org/wiki/view/Asterisk+echo+cancellation but it does not seem to have made much difference. Currently we are using a X101P for the POTS line and a TDM401B (TDM400P with one FXS port) for the conventional telephones. From what I have read, it may help to use an FXO port on the TDM400P rather than the X101P for the POTS line. What is the "conventional wisdom" about the echo in this configuration and what causes the crackle and how should I tackle that? I have tried rebooting/power-cycling the machine to reset the hardware but it really hasn't noticeably helped. Is there anything else that I can try? Thanks, Mike
I will agree that switching to the TDM card significantly helped my echo and sound quality, I would take a second to point out that interrupt sharing on your * server might cause crackling-like noises. Try lspci -vb and cat /proc/interrupts to see if you discern any hardware using the same irq the x101p is. Also run zttest in the zaptel source directory and see what the average number is. s/b 100%, but I believe as low as 98% or thereabouts should have pretty acceptable call quality. If it dips even lower than that regularly, or concurrently with the crackling sounds, then your server is probably working too hard on irrelevant processes or has irq sharing issues. Moj M.Hockings wrote:> We are running asterisk with a single POTS line for local calls and a > voip line for long distance. Whenever we receive a call on the POTS > line it is more than likely, but not always, going to have significant > distracting echo. In addition to that there is occasional heavy crackle > or static. I have tried to follow the guidelines at : > http://www.voip-info.org/wiki/view/Asterisk+echo+cancellation > but it does not seem to have made much difference. > > Currently we are using a X101P for the POTS line and a TDM401B (TDM400P > with one FXS port) for the conventional telephones. From what I have > read, it may help to use an FXO port on the TDM400P rather than the > X101P for the POTS line. > > What is the "conventional wisdom" about the echo in this configuration > and what causes the crackle and how should I tackle that? I have tried > rebooting/power-cycling the machine to reset the hardware but it really > hasn't noticeably helped. > > Is there anything else that I can try? > > Thanks, Mike > > _______________________________________________ > --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 >-- Mojo <mojo@horanappraisals.com> Office Manger, Horan & Company, LLC (907) 747-6666 x112
Mojo with Horan & Company, LLC wrote:> I will agree that switching to the TDM card significantly helped my echo > and sound quality, I would take a second to point out that interrupt > sharing on your * server might cause crackling-like noises. Try > > lspci -vb > and > cat /proc/interrupts > > to see if you discern any hardware using the same irq the x101p is.lspci does not show the IRQs *after* ACPI is enabled. /proc/interrupts does. -- Now accepting new clients in Birmingham, Atlanta, Huntsville, Chattanooga, and Montgomery.