On the 908e (or any 9XXe) gen 1 and gen 2, only T1 ports 3 and 4 can be used to terminate PRI or CAS. T1 0/1 and 0/2 are for data only. There's a subtle hint about this printed next to the connectors themselves.
interface t1 0/2
interface t1 0/3
description PRI Handoff to 7100
tdm-group 3 timeslots 1-24 speed 64
interface pri 3
description pri 3
no connect t1 0/2 tdm-group 3
connect t1 0/3 tdm-group 3
role network b-channel-restarts enable
Then move the cable from T1 0/2 to t1 0/3.
You will probably need a T1 crossover cable between the TA908e and the 7100. This is different from an Ethernet crossover and you'll likely have to wire it yourself. If the T1 itself is down (red light on TA908e) then try a crossover cable.
A end B end
Pins 3, 6, 7,and 8 can be omitted or wired straight, they're not used.
Ok that explains it. If I use t 0/3 it works fine. Thank you very much for help.