T1: A Survival Guide

T1 Installation and Termination

After you place an order for a T1, be prepared to wait. Avoiding crosstalk on T1 circuits requires that the telco carefully select the wire pairs in a conduit. Repeaters must be adequately separated so that they do not interfere with each other, but must be close enough together to regenerate and recondition the signal. Line cards may be needed at each CO involved. Delays of a month or more from the initial promised date are not uncommon with the installation of high-speed links.

All the waiting does offer you the opportunity to gather the equipment you need and nail down the configuration. When you’ve ordered the circuit, the telco will give you the basic configuration information (line coding, speed, and build out). T1s are priced based on distance. To save money, you could purchase a T1 that links to the nearest entry point to a public data network, such as the telco’s regional frame relay net. This is illustrated in Figure 7-1. You’ll need to find additional configuration information for connections that are not made directly to the ISP.

Figure 7-1. Using a public frame cloud to cut the distance

The Demarc

A telco technician will come to your site to connect the circuit. After the telco brings the line from the CO to the building, the technician installs a jack of some sort, which is often called the demarc. Anything beyond the demarc is up to you ...