https://td-2.org/ 2026-04-29T13:18:59+00:00 https://td-2.org/ https://td-2.org/_media/wiki/logo.png text/html 2026-04-04T21:46:19+00:00 Anonymous (anonymous@undisclosed.example.com) https://td-2.org/carriers/coaxial?rev=1775339179 Coaxial Cable (L-Carrier) Types Four major L-carrier standards are called L-1, L-3, L-4, and L-5. There also exist variants L-3I (L-3 Improved) and L-5E (L-5 Enhanced?). L-2 did exist but was never installed on any substantial scale, only really on a pilot system between Baltimore and Washington. The different L versions mostly just reflect ongoing improvement of the standard, but there is some degree of purpose-specificity as the higher capacity of L-4 and L-5 made them more practical for maj… text/html 2024-08-03T03:54:22+00:00 Anonymous (anonymous@undisclosed.example.com) https://td-2.org/carriers/l-3i_repeater_station?rev=1722657262 L-3I Repeater Station The actual equipment at an L-3I repeater station is installed underground in a concrete vault. For the safety and comfort of technicians performing maintenance, there is a distinctive metal shed above ground. In many cases today, the shed has been removed, leaving only the concrete foundation and hatch into the vault (universally welded shut). text/html 2026-04-05T23:46:33+00:00 Anonymous (anonymous@undisclosed.example.com) https://td-2.org/carriers/start?rev=1775432793 Long-Distance Carriers AT&T used the term “carrier” for multiplexing schemes. This is a reference to the common types of carrier used in the long-distance telephone network. * analog open wire and cable (A-K carrier) * Coaxial Cable (L-Carrier) * microwave * fiber