PAT:
Please, DO NOT DISPLAY my email address... neither in the "From" line nor in the "Reply-to" line.
Mark Roberts ( snipped-for-privacy@myrealbox.com) wrote:
Indeed, the San Francisco "West Bay" area (including north of the Golden Gate area) was dialed from Englewood NJ with 318, not 415, in this 1951 original customer long distance dialing plan.
The reason that the East Bay was dialed from Englewood with 415 (the ultimate area code for the entire Bay area until the East Bay split off initially to 510 in 1991) while the West Bay (San Francisco) was dialed from Englewood with 318, is not really stated anywhere.
It couldn't be that there were "duplicate" NNX central office codes/ names/letters in use in the entire Bay area, since "cross-bay" calls had already been dialed as just 2L-5N and continued to be dialed as such for many years to come (I assume until 510 split off for the East Bay, split from 415 in 1991).
The only explanation that has been given by some is that AT&T wanted a more discrete way to identify each side of the Bay for both customer reference purposes, as well as for more discrete routing and rating purposes. Both sides of the Bay had their own tandem or toll switches, and I only assume that Englewood's toll switch or local No.5 Crossbar needed an upfront way to identify the East Bay (415) from the West Bay (318) up-front, to then route the call directly to the Oakland tandem (415) vs. the San Francisco tandem (318).
This was only a temporary measure, and I wonder if it might have really been possible to dial either area code for either side of the Bay when dialing from Englewood NJ back then. Official Bell System area code maps I've seen from the early 1950s make no mention of 318 at all. These maps show only 415 for all of northern central California along the Pacific Coast. Of course, only the metropolitan Bay area was intended to be customer dialed from Englewood in
1951. While area codes date back to the late 1940s and there was a developed and continued developing area code format throughout the 1950s, most of them were used only by operators at the time, while customer originated DDD was slowly growing as well as the number of locations which could be dialed by such customers with DDD. 318 was NOT listed as one of the original 1947 area codes, neither. I don't know when Bell actually reclaimed it from use from Englewwod NJ customers. I don't even know if the experiment at Englewood NJ beginning November 1951 even had any official "end date".If customer-originated long distance dialing from Englewood NJ continued on without any interruption, by 1953 or so, there really wouldn't have been a need for a separate 318 from 415, since originating local and toll crossbar switching at Englewood would have had more recent upgraded translations equipment to be able to determine East Bay vs. West Bay by analyzing the entire 415-NNX code as dialed by the customer, instead of analyzing only the three-digit area code up-front needing to determine East Bay vs. West Bay upfront by 415 vs. 318.
But by 1957, AT&T assigned 318 to northern, central, south-central, and southwestern Louisiana, splitting from 504. And 318 is now just northern Louisiana, since 337 split from 318 in 1999 for south-central and south- western Louisiana.
- Anthony Bellanga