I know this post is a bit old, but I thought there might be some
interest in what a quick hour of research was able to dig up in the
Oakland History Room of the Oakland Public Library ...
Anthony Bellanga <firstname.lastname@example.org> had written:
> Regarding Lisa Hancock's post on Oakland and San Francisco and
> 2L-4N numbering ...
> San Francisco and Oakland were 2L-4N thru at least the end of WW-II
> (i.e., mid-1940s). I don't know if the entire area was flash-cut to
> 2L-5N or if it were phased, and if it were phased over, how long it
> would have taken.
I have been able to nail it down, for the East Bay at least, to
sometime between 1946 and 1948. I can't get any closer because the
telephone directory for 1947 was not available.
For those of you who are interested, here are some of my notes. I
originally did this to research some oddities we have here with
respect to rate center-switch combinations. Note especially the
strange appearance of the "530" prefix in 1965 and the "911" service
code in brief use after WWII.
Directories available - 1935, 1944, 1946, 1948-53, 1958-66.
The 1954-57 gap is a key gap. This appears to be when dial service
was fully implemented.
From 1960 or 1961, the list of exchange names and rate centers,
all of which are extant today unless indicated otherwise:
Main-Piedmont [need to get third digit]:
KEllog (yes, one g)
Trinidad (includes San Leandro)
Contra Costa County exchanges that were local calls:
Orinda - CLifford
Lafayette - ATlantic
Walnut Creek - YEllowstone
Moraga - DRake
Concord - MUlberry
Contra Costa phones appeared not to be dial into 1953 according to
instructions in the local calling guide.
Montclair phone numbers:
Phone numbers in the hills changed between May 1964 and June 1965
directory. This must have been when OKLDCA13 was built. Main-Piedmont
rate center (e.g. most of Montclair business district) changed from
OLympic numbers to 339. Fruitvale rate center (Montclair Methodist
Church, areas S of Snake Road/ Shepherd Canyon Road, i.e. the old ROW
for the Sacramento Northern railway) changed from ANdover or KEllog
numbers to 531. I should have checked to see if there were similar
changes in the Glenview, Oakmore, Dimond, or Laurel Districts.
Probably so. Imagine the huge effort it took to cut phones over to a
=> In the 1965 directory, *two* new prefixes were listed in the
local calling pages for the Fruitvale rate center: 531 **and** 530!
In the 1966 directory, only 531 was listed. I did not see any phone
numbers with 530 listed in the 1965 directory. Years later, of
course, 530 was added to the Fruitvale-OLKDCA13 rate center-switch
Did someone at Pac Bell jump the gun? This is the earliest I have
ever seen a prefix of the form xx0.
Dial service and numbering schemes:
Phone numbers were six digits (2L-4N) in 1935. There is no clear
indication as to which numbers were dial and which were not other than
"J" or "W" suffixes. Interestingly enough, 211, 411, and 611 service
codes were already established for dial phones. No DDD, of
course. One-page, bare-bones introduction. Opening a 70-year-old phone
directory is a great way of generating sneezing fits. The Bell Gothic
typeface was not in use at this time.
The 1935 directory also included just about *every* Bay Area
community. Oakland-Piedmont-Berkeley-Alameda were listed first, then
the business directory, then San Francisco, then San Mateo and San
By 1944, there was mixed 2L-4N and 2L-5N numbering. Unclear, but it
appears that 2L-5N phones were always dial phones. Occasionally 2L-4N
numbers appear with "J" or "W" suffixes. Bell Gothic typeface in use.
In 1946, "911" was used as a service code for dial phones to reach
Hayward telephone numbers.
The 1947 directory is missing. By 1948, all phones were 2L-5N. "J"
and "W" suffixes were retained. Most notably, this was for the
"BErkeley" exchange (BErkeley 7, would have been "237" had it
survived) and "PIedmont" (PIedmont 5, would have been "745" had it
Also by 1948, "911" disappeared as a dialing code for Hayward but
instead was a dialing code for LAndscape numbers (Berkeley) to reach
By 1948, apparently BErkeley, AShberry (3), PIedmont, and HUmboldt (3)
were operator-assisted exchanges. Montclair phones in Main-Piedmont
rate center were mostly PIedmont numbers. But it may have been a mixed
dial-operator area, because there were a few OLympic 2 or OLympic 3
numbers by then. Montclair phones in the Fruitvale rate center were
By 1958, PIedmont, AShberry, BErkeley all were gone as exchanges.
(N.B. There's a key gap here because the 1954-57 directories are
missing or not available.)
The last year that 2L-5N numbers were used exclusively was 1960.
Local dialing guide shows one 7N prefix in 1961 (849), but individual
listings still were shown. Oddly, some listings showed only the letter
prefix (OL) while others showed the full name (OLympic). Users were
advised to look up the full prefix name on a page in the front. Was
this due to production limitations (after all, we're talking hot metal
A few more 7N numbers (3N prefixes) showed up in 1962. Where
applicable, though, individual listings showed the 2L prefix, either
in the short form or as full name.
The May 1963 directory was the first to list all numbers in the 7N
form. The local calling guide still listed prefix names where
The May 1964 directory listed only the 2L prefix abbreviation, and
not the full prefix name in the local calling guide.
The June 1965 directory is the first one to show the realigned numbers
in the hills.
The local calling guide is missing from the June 1966 directory, but
approximately half the list of rate centers and message unit charges
still is extant.
There's an odd statement in May 1964 directory in the area code
listings, "To make a direct Distance call, just dial the Area Code and
then the telephone number". Does that mean no "1" or "211" was used?
The 1960 directory gives "211" as the Long Distance number but some
(not all) locations could be direct dialed.
> Bell System journals of the early 1950s which dealt with Area Codes,
> DDD, etc. always referred to JUST 415 if there was a map included in
> the article. The use of 318 was only for instructions for Englewood NJ
> customers. But again, the use of 318 *AND* 415 for this situation was
> *NOT* because of any potential duplication of c.o.codes/names/letters
> ... since both sides of the Bay could already "locally" dial each
> other on a "pure" 2L-5N basis (and quite possibly a "pure" 2L-4N basis
> prior to the mid/late 1940s).
It appears that they could dial each other 2L-4N in 1935, as indicated
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