For Asterisk users who connect to the PSTN, echo with the voice communication is possible and can be managed effectively with echo cancellation solutions from Digium. Asterisk itself offers a range of software-based open source echo cancellation routines that are moderately effective in eliminating the echo that most Asterisk users experience. However, there are cases in which these algorithms are not effective. To combat this, Digium offers a line of DSP-based echo cancellation modules for all of our analog and digital (T1/E1/J1) cards with the VPMOCT series modules. | |