i have a customer with 1232- 6 equiped with a t1 card , xdp port enabled , outgoing line permissions enabled , reference trunk set for 1st access , no restrictions set , inbound calls work fine , calls other ext.'s ok , when placing an out bound call 9 + # you get a fast busy , trying 8 plus trunk group #'s same problem , power down the system , works for one or two calls then the problem comes back

We don't have ti here just pri ISDN, and the pri settings are referenced to 1 co port, ours is preset as co 9, I had a problem where I disabled the co port and is stopped access to the pri.
Not sure if the t1 is the same or not.