Exchanges in the San Francisco Bay area



Because telephone exchanges in the entire San Francisco Bay area, including San Francisco, Oakland, San Jose, and many smaller communities, were closely connected, a single section of this Website is intended to cover the entire area. (See the map below, which defines the local calling area in 1960, though very similar maps would have been available much earlier.) The history of the telephone exchange names in the Bay Area, as in most significant United States cities, can be divided into three periods:

  1. The pre-dial period, when all telephone calls were completed by manual action by operators, and there were no constraints on exchange names other than that there was no likelihood of confusion when a customer gave the name to the operator,
  2. The early dial period, in which the Bay Area telephone numbers were set up to accommodate dialing the first two letters of an exchange name followed by a four-digit number designating the individual line, though in fact not all exchanges provided for dialing by the phones in those exchanges, and
  3. The late dial period, in which, instead of the first two letters of an exchange name alone, one dialed the first two letters and an "office number" (This was the terminology used in an early New York City directory, though it was not common terminology in this period), again followed by four digits designating the individual line. It may be noted that, although San Francisco is a smaller city than many others that took a longer time to transition from the early to the late dial period, the fact that the entire Bay Area constituted a local calling area made the total population larger, and thus this transition began no later than 1947, and was completed by 1951, though precise dates are unknown to me.

At this time, I have no information about the Bay Area exchanges in the pre-dial period and only a very small amount of information in the early dial period. There is more information on the late dial period, mostly thanks to Alan J. Sachs, who provided both new data and links to additional data. To access this information click here. (While links to the pre-dial and early dial periods are provided, they will not provide any data at present; they are only here for future use.)




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Last modified August 30, 2015.


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