This data informs which echo cancellation algorithm to be used by default: 165 or 168 for a particular channel. The numbers 165 and 168 are the ITU designations for the algorithms. The number following the designation describes the echo tail length in milliseconds. Both G.165 and G.168 are ITU-T recommendations. G.168 has slightly stricter technical specs. G.168 defines much better how the tests are performed. If an echo canceller passes the G.165 spec, then it is G.165 compliant. If it passes G.168, it is both G.168 and G.165 compliant. The echo tail length required depends on factors such as network configuration, local loop length, line frequency response, etc. Generally, 16 ms is more than adequate for local loop (ie. Zedge) and 32 ms is a good minimum for Network side. Our products currently support up to 48 ms of echo tail length, MALC supports 16 ms of echo tail length. Valid values for the variable are: * off - echo cancellation is off (on all platforms). * g165EchoTL16 - G.165 echo cancellation with echo tail length of 16ms (on MALC only). * g168EchoTL48 - G.168 echo cancellation with echo tail length of 48ms (on the other platforms, i.e.: BAN, Sechtor 100, Z-Edge64). Following values are not supported: * g165EchoTL32 - G.165 echo cancellation with echo tail length of 32ms. * g165EchoTL48 - G.165 echo cancellation with echo tail length of 48ms. * g168EchoTL32 - G.168 echo cancellation with echo tail length of 32ms. * g168EchoTL64 - G.168 echo cancellation with echo tail length of 64ms. * g168EchoTL80 - G.168 echo cancellation with echo tail length of 80ms. * g168EchoTL96 - G.168 echo cancellation with echo tail length of 96ms. * g168EchoTL112 - G.168 echo cancellation with echo tail length of 112ms. * g168EchoTL128 - G.168 echo cancellation with echo tail length of 128ms. The default value is g165EchoTL16 for MALC, and g168EchoTL48 for the other platforms.