T1: A Survival Guide

Pre-Connection Tasks

When the circuit is up and the ISP is ready, the ISP will call to complete the circuit turn-up. When everything goes according to plan, this usually happens a day or two after the telco installs the circuit. If the telco circuit is delayed, the ISP may be ready whenever the telco is finished and may even await your call. During this time, there are a few things you can do to make sure the turn-up is smooth:

1. Check that you have the proper cables to connect your CSU/DSU and router. You will probably need to obtain a V.35 cable from your router vendor; most vendors use proprietary serial-port pinouts and require you to buy special cables. If you are ordering new equipment, such as a router with a V.35 port, make sure that you ask the vendor if you’ll need a new cable.

2. To connect the CSU/DSU to the telco network, you’ll need a second cable—most likely one with an RJ-48 jack (also sometimes called an RJ-48C or RJ-48X; see Appendix E for details). RJ-48 uses wires 1 and 2 as a pair and wires 4 and 5 as a pair. To prevent crosstalk, make sure that the component wires of each pair are tightly twisted together: the wires leading to pins 1 and 2 should be twisted together, and the wires leading to pins 4 and 5 should be twisted together. Twisting the appropriate pairs together is only the minimum step. Long runs should use shielded wiring.

3. Configure the CSU/DSU. If the ISP included the CSU/DSU, they may have shipped it preconfigured for installing the line. Nevertheless, ...