L System
- See L-system for information on Lindenmayer systems.
Transcontinental Cable System - L System
| System | Year | Frequency | Coax per cable | Distance between repeaters | Capacity |
|---|---|---|---|---|---|
| L-1 | 1941 | 3 mhz | 4 | 8 miles | 600 voice circuits |
| L-2 | 1942 | 840 khz | 4 | 16 miles | 360 voice circuits |
| L-3 | 1953 | 8 mhz | 8 | 4 miles | 5,580 voice circuits |
| L-4 | 1967 | 17 mhz | 20 | 2 miles | 32,400 voice circuits |
| L-5 | 1972 | 57 mhz | 22 | 2 miles | 132,000 voice circuits |
The Transcontinental Cable System was developed by AT&T to create a hardened telecom network for civil defense related communications during the cold war. There were five phases of development of the system, designated L-1 through L-5.
The system was designed to provide for land line connections between key command and control facilities inside the United States. Starting with L-4 the system was upgraded to withstand a nuclear attack. The system consisted of over 100 "Main Stations" and 1000 individual repeater vaults. The "Main Stations" had generators, blast doors and accommodations for staff for a two-week post-attack period.
In the late 1970s and early 1980s the system was determined to be redundant with the advance of satellite based communications. Most stations were never upgraded past L-4 due to advancement of technology.
One use of the system was for nuclear early warning systems and blast detection.