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SAN DIEGO TANDEM CENTRAL OFFICE

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  San Diego "University" was originally built by the Pacific Telephone & Telegraph Office in the late 1920s as a manual office serving customers in the North Park and Hillcrest areas of San Diego. As the region grew the main toll office was served by the "C-Street" office downtown. Direct Distance Dialing was established in San Diego in April 1958 with San Diego established as a Primary Center with direct trunk groups to the Los Angeles Regional Center. San Diego was rehomed onto the San Bernardino Regional Center in 1961. When TD-2 microwave service was introduced in the late 1950s, Pacific Telephone and Telegraph Company moved the tandem and built a new toll office at the "University" site some two miles to the north and away from the core downtown area. One of the reasons for the move was the ability to expanded the toll office for future growth as well as its heightened "elevation" above the downtown area. The C-Street office was located near the San Diego Bay and the surrounding hills made microwave radio service difficult without the construction of a rather tall tower. The University location was located on a costal bluff so had great visibility to surrounding areas with a rather modest microwave structure.   The first TD-2 microwave route was established to Los Angeles via San Diego-Boucher Hill-Santiago Peak-Los Angeles. A #4 Cross-Bar Tandem switch was installed in May 1967 (SNDGCA0245T) and in April 1978 AT&T installed a 4ESS toll switch (SNDGCA0787T) with San Diego then becoming a Primary Center with direct trunk groups the the San Bernardino Regional Center. Intertoll routes from San Diego were to Oceanside, Escondido, El Centro and to Tijuana, Mexicali and Ensenada, Mexico. Today San Diego is considered an International Gateway with direct connections to Tijuana, Mexicali, Tecate and Ensenada, Mexico.  San Diego is also connected to Los Angeles, Anaheim, Riverside, San Bernardino and Phoenix via Fiber routes.

Microwave long-haul paths from San Diego were: Black Mountain, Boucher Hill, El Cajon, Julian and Tijuana

Another view looking

   Microwave structure on the top of office

  Microwave antennas pointing south. Path to Mt. Charleston

  Overall view of complex with

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