TELECOM Digest OnLine - Sorted: More on San Francisco and Oakland Numbering

More on San Francisco and Oakland Numbering

Mark Roberts (
Mon, 24 Oct 2005 01:15:06 -0000

Thanks to the clipping files at the History Room of the Oakland Public
Library, I have been able to pin down the date that San Francisco and
Oakland went fully to 2L-5N numbers: August 10, 1947, a Sunday, at 12

The Tribune referred to it on Saturday, which would have been August
9, of course, but it also is clear from the context that the
switchover activities began on Saturday night. Either the Tribune's
style considered the day to begin at 12.01 am, or there was some
confusion when the story was edited.

An article in the August 7, 1947 Oakland Tribune started out:

When you're enjoying your leisure Sunday, think of the poor telephone
workers. They're going to be plenty busy.

For at exactly 12 midnight Saturday [see above for why I believe this
was really Sunday], new numbers for some 325,000 telephone subscribers
in the Oakland area and San Francisco go into effect, and Pacific
Telephone and Telegraph Company officials have prepared for trouble.

For months now, a new telephone directory, advertisements, radio
announcements, printed pamphlets and various other media of public
enlightment have proclaimed the impending change. Even "Bugs Bunny"
has been borrowed from Hollywood to do his part in helping the public
ease into the change with as few complications as possible.
[Unfortunately, there is no further explanation of the role Bugs Bunny
played in transition to 2L-5N telephone numbers.]


Nevertheless, there will be mix-ups -- and plenty of them. People just
don't make a change from anything so established as telphone numbers
without a slip along the line somewhere. And, even if they do remember
the new numbers the first day, telephone officials are predicting
they'll forget the next day or the day after and let habit dictate
their dialing.

That's why an unusually large force of operators will be on duty when
heavy traffic begins around 6 a.m. Sunday. The "trouble and
interceptor" panel at the local office will have a full complement of
operators as will the regular local boards through which most of the
3,000,000 daily calls pass.

Telephone officials estimate five per cent of these calls, or about
150,000, will be incorrect.


In addition, a gadget known as a "mirrorphone" will be in
operation. It's the same record machine that said "No" to you when you
tried to use your phone during the recent telephone strike. This time
it will volunteer the information that you've dialed the wrong number
and "please look in your August 10th directory for the new number."

The change is a step toward the extension of direct dialing to nearby
communities and future operator-dialing of long distance calls to
distant cities. It will affect cities on this side of the Bay from San
Leandro on the south to El Cerrito on the north. [El Cerrito is just
south of Richmond.]

In effect, the change consists of adding a numeral, known as an
"office numeral", to the familiar prefixes, such as TEmplebar,
GLencourt or HIghgate. Thus, TEmplebar 0000 will become TEmplebar
2-0000. The KEllogg [sic], LAkehurst, LAndscape and LOckhaven
exchanges have had office numerals for some time and will not be


Addition of the numerals increases the possible number combinations on
the present dials from 60 to 600. [Does the Tribune mean number
combinations of possible exchanges? There's no further explanation of
the number.] All the combinations won't be utilized immediately, but
they'll be available when dial service is extended in the future. Too,
the new numeral will increase dialing time from an average of eight
seconds to about 11 seconds.

Technically, the change of numbers is relatively simple, and will be
accomplished with nothing more than wire and a soldering iron. Wires
will be changed in the "decoder banks," wiring panels which receive
the combination you dial, and sets up the correct dial code which
feeds back into the right dial exchange in one-fifth of a
second. [Huh?]

Wiremen in the various offices will cut on of the decoders in an
exchange out of operation when traffic begins to slacken around 10:30
pm Saturday. Between then and midnight, they will rewire that one bank
to take care of the new numbers and put it into service when the other
decoder banks [are] cut out at midnight. That one bank will be
sufficient to handle all calls made during the early hours of the
morning while workmen are rewiring the other banks. All the banks
will be ready for operation when the heavier traffic begins around 6


=> Now here's the odd thing. Certain exchanges, such as PIedmont,
continued to have "J" or "W" suffixes after the phone numbers. These
were, of course, the exchanges that had not yet gone to dial
service. Here's what the "How to Dial" section of the 1951 directory
explained what to do with those numbers:

3. Dial the first two letters and the numeral of the central
officename, then the remaining figures of the number. If
the figures are followed by a letter, such as W, J, R,
or M dial this letter also.

In other words, there was, for a time, 2L-5N-1L dialing to some

Dialing instructions in the 1949 and 1951 directories indicated that
cross-bay calling, e.g. Oakland to San Francisco, could be dialed only
from "dial individual line business telephones" (except coin
telephones). All others still had to use an operator. Calls within the
East Bay were dialed, or required the operator's assistance, or from
Berkeley LAndscape to Richmond, required dialing "911". (I referred to
this service code in a previous post; in 1948 that code was used for
calls to Hayward, but it could be dialed by 1949.)

The change to 2L-5N dialing was announced in January of 1947. A
couple of paragraphs in a Tribune story may be of interest:

California has more than 2,635,000 telephones in use, which places
it second in the nation for telephone usage ... It has more than
333,000 unfilled telephone orders, also a second place record.

In the Metropolitan Oakland zone, 221,907 telephones were in use
in 1946, as compared to 167,199 in 1940, and 18,372 unfilled
applications still remained at the exchange. [January 9, 1947]

Another Tribune story on January 28, 1947 gave the names of the
exchanges affected by the addition of a digit: ANdover (1), AShberry
(3), BErkeley (7), GLencourt (1), HIghgate (4), HUmboldt (3), OLympic
(2), PIedmont (5), SWeetwood (8), TEmplebar (2), THornwall (3),
TRinidad (2), TWinoaks (3), ROchester (7).

Other stories in the clipping file described the conversion of
Berkeley's THornwall exchange (THornwall 1 and THornwall 3) to dial
service on August 29, 1954, the final conversion in the bayside East
Bay, for THornwall 8 (formerly AShberry) on April 19, 1959, and the
last conversion in the Bay Area, in Crockett on November 11, 1969.

Alas, there were no clippings regarding the 1965 (or 1964) spinoff of
Oakland Hills numbers in the Fruitvale and Main-Piedmont rate centers
into their own switch. I ran out of time and didn't have a chance to
go through newspaper microfilms. I would assume that there would have
been some publicity for it.

Mark Roberts | "A man does not show his greatness by being at one extremity,
Oakland, Cal.| but rather by touching both at once."
NO HTML MAIL | -- Blaise Pascal

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