The Federal Telecommunications System

Beginning operation in 1963, the FTS was a "private" long-distance telephone network serving the civilian agencies of the federal government. It was built and operated by AT&T under contract to the General Services Administration, a federal agency which provides a wide variety of support services across the entire civilian sector of the federal government. The FTS has been replaced by the Federal Telecommunications Service 2000.

The FTS design used a hierarchical arrangement of switching centers, or "switches". In this system, every switch was assigned to one of several "ranks". The switches were connected to certain other switches, of the same, higher, or lower rank, by trunk lines. A trunk line (or simply "trunk") is a circuit which carries a call between switches. When an FTS subscriber placed a call to a phone outside the territory of the switch serving his line, that switch would attempt to find a route to the destination switch through the lowest possible levels of the hierarchy, advancing to higher levels as needed until a route was established. This strategy helped make efficient use of network resources by minimizing the number of trunks and switches used to complete a call.

This online book includes a History of the FTS.

In the Washington area, FTS switches in two AT&T facilities in Maryland. Both installations are still active in the AT&T network, and in accordance with a request from AT&T Corporate Security, their names and exact locations are not published here. Photos and a description of one of these facilities can be viewed on my AT&T Long Lines web site, under the fictitious name MD-1.

Another FTS switch was located in Illinois, at a facility whose Common Language Location Identifier (CLLI) is NRWYILNO.

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Updated on September 28, 2002 at 10:48 by Albert LaFrance