[Freeswitch-users] The Usage of uuid_preprocess && echo cancellation

Hi: 1. can any one know the usage of uuid_preprocess? 2. according to the FreeSwitch code, this command would add a bug to the uuid session, initialize echo parameters, and in functions switch_core_session_read_frame/switch_core_session_write_frame do echo handle. but the echo still exist. do any one help me ? thanks.. Echo Scenes: Telephone 1000, 1001 registered the FreeSwitch, 1000 call 1001, 1001 answered( two of them are handfree, producing scary sound); Try Solution: Launch the command-line ulility: #> fs_cli #>: show channels uuid1, uuid2 #>:uuid_preprocess uuid1 recho_cancel=true; #>:uuid_preprocess uuid2 recho_cancel=true; but the echo still exist. can any one help me, thanks!