T1 Crossover Cable, Loopback Plug

The image displayed shows the cross-over cable pinout for a standard T1.  This cable should be plugged into your Smartjack (provided by the Carrier) and your PBXtra 's PRI card (Sangoma A10X model of cards).

Alternatively, Smartronix (example) sells T1/E1 or ISDN/PRI crossover adapters (same wiring, different colors - one is pale greenish-white or mint, the other is yellow).

If purchasing an adapter, make certain you get at least one crossover adapter.  Loopbacks are for testing.