Hello all, If you like to assign different E1 to different client follow bellow: step 1: group your E1s edit : /etc/asterisk/chan_dahdi.conf group=1 cicbeginswith=1 channel=1-15 cicbeginswith=17 channel=17-31 group=2 cicbeginswith=32 channel=32-62 group=3 cicbeginswith=63 channel=63-93 group=4 cicbeginswith=94 channel=94-124 step 2: edit : /etc/asterisk/extensions.conf ; Dial plan for 1st E1 exten => _110XXXXXX.,1,Dial(DAHDI/g1/${EXTEN:2}) exten => _110XXXXXX.,n,Hangup ; End of 1st E1 ; Dial plan for 2nd E1 exten => _220XXXXXX.,1,Dial(DAHDI/g2/${EXTEN:2}) exten => _220XXXXXX.,n,Hangup ; End of 2nd E1 ; Dial plan for 3rd E1 exten => _330XXXXXX.,1,Dial(DAHDI/g3/${EXTEN:2}) exten => _330XXXXXX.,n,Hangup ; End of 3rd E1 ; Dial plan for 4th E1 exten => _440XXXXXX.,1,Dial(DAHDI/g4/${EXTEN:2}) exten => _440XXXXXX.,n,Hangup ; End of 4th E1