I’ve been running asterisk for years with Digium TDM* cards. I’m looking to migrate the asterisk server to an Intel Atom D525-based unit and to do so I need to purchase a PCI-E AEX* card. However, I’m trying to determine if my existing card has the hardware echo cancellation module. Short of unracking the server and taking it apart to look at the card, is there a way to figure out if the card has the echo cancellation module? (System is Debian Linux, Asterisk 1.8.1.1).
Related to that, does anyone have experience with the D525 platform? Will an echo cancellation module even be needed for a minimal workload? (Two PSTN lines, up to 3 VOIP calls simultaneously).
With regards to your second question, the echo cancellation is required regardless of the load. The echo is generation is due to acoustic factors and/or hybrid. If you do not want to spend on a hardware echo cancellation you can try the build-in echo cancellation of Asterisk or try one of the following:
To see if an echo can cancellation module is present, here are the steps:
Reboot your system, then once dahdi and asterisk are started, on a linux console enter the following:
dmesg |grep VPM (notice VPM is in uppercase)
It will display information about a VPM module being operational. If it does not display anything, then there are no echo can module installed.