ISDN trunk - Problem with outgoing calls

[hung.le]

Hello everyone,
I have a customer who is using OXO R10.2 with ISDN trunk line.
- incoming calls throught ISDN trunk line are OK
- But i have problem with the outgoing calls throught ISDN trunk line: If one extesion make outgoing call via ISDN trunk line, others extensions can not make outgoing calls via ISDN trunks (it means only one call only via ISDN trunk) and get the busy tone when press Trunk Group sieze prefix.

If anybody has the same problem before, pls share with me.

Thanks!

[vad]

Check - External lines/ list of accesses/ your T2 access. Item - No of B-Chan. (and type - incoming/outgoing/bi-directional).
In common case - you need 30 channel, bi-directional.