Duration Mis-match asterisk and telecom operator


We use Asterisk with ISDN E1 lines in India and have noticed there are some minor differences in the call duration as calculated by asterisk and as billed to us by the operator. Normally the Asterisk server gives a higher duration as compared to what the operator bills us.

Any explanations ??


There are two fields in the cdr the duration, this field count since the call arrived in the PBX and the billsec that counts since the call was answered.

all our calls are outbound so no question of call coming into the pbx as we originate the calls using call files.

I think that this is normal. Local PBX and provider timers never match. Asterisk call times are only for internal reference, the providers times are used with billing.