When experiencing echo problems on a PRI/Analog trunk, one must turn on echo canceller to alleviate such issues. On PBXware 3.x this is done manually by editing the trunk, click on Advanved Options, scroll down then click on Additional config.

In the config field you must put following line:

echocanceller=<echocanceller name>,<channel(s)>

There are different echo cancellers compiled in the DAHDI package that comes with PBXware. The reason for several echo cancellers is that customer can chose which one to use, which one gives best results with the echo issue that customer is experiencing.

Valid echo cancellers are: mg2, kb1, sec2, and sec.

Example:
Configure channels 1 through 8 to use the mg2 echo canceller

echocanceller=mg2,1-8

And change channel 2 to use the kb1 echo canceller.

echocanceller=kb1,2

After every addition/change that is made to echocanceller line, restart of PBXware is needed. You will restart PBXware by executing:

/opt/pbxware/sh/pbxware restart

As stated, there are four echo cancellers and customer needs to try which one suits the best for his echo issues.