Well, to simplify things you should be able to disconnect the rj48 cable connecting to the terminal pins and plug in the straight thru connection to the router. Straight Ethernet cabling is fine.
If you really want to be a phone man, You can also strip an end off of an Ethernet cable and strip the orange and green pairs and screw them down as such...
Pinouts for T1/E1 Port (RJ-48C)
Pin1
Signal Ethernet Westell T1 Dmarc CO signal
1 RX (input) Orange/White CT tip
2 RX (input) Orange CT1 ring
3 - Green/White - -
4 TX (output) Blue CR tip
5 TX (output) Blue/White CR1 ring
6 - Green - -
7 - Brown/White - -
8 - Brown - -