1944 directory 1

For many years, the phone company used named Telephone Exchanges to refer to blocks of numbers. Initially, they were just station names; later, the first two letters of the name corresponded to the first two digits of the phone number, with 2=ABC, 3=DEF, 4=GHI, 5=JKL, 6=MNO, 7=PRS, 8=TUV, 9=WXY, 0=Z (note there is no Q). For example, the number for the Paramount Theatre in 1944 was TWinoaks-2300, or 89-2300. The rapid growth of phone numbers and the addition of direct-dialing (especially for long distance) led to the phase out of named exchanges.

In the early days, reaching another number meant lifting the receiver, waiting for the operator, and then asking for the person. This quickly evolved into named stations and a series of 2, 3 or 4 digits. At the time, being in the same exchange meant the 10,000 possible phone numbers were connected to the same physical switching system, and so generally referred to a geographic area. Initially the numbers were 2 letters plus 2-4 digits. In the late 1940s, that expanded to 2 letters plus 5 digits ("2L-5N"). For the Paramount, a digit was added and it became TWinoaks3-2300, or 893-2300.

Area Codes

A related topic is area codes, which went through a similar expansion. The 415 area code was one of 3 area codes in California created in 1947. On September 2, 1991, the 510 area code was split off to cover the East Bay including Oakland.

1923 Exchanges

Exchange Areas
Alameda Alameda
Berkeley Berkeley
Fruitvale Oakland
Elmhurst Oakland
Humboldt Oakland (ref)
Lakeside Oakland
Merritt Oakland (12th Ave.)
Oakland Oakland
Piedmont Oakland, Piedmont
Thornwall Berkeley

1928 Exchanges

Exchange Areas
ALameda Alameda
ANdover Oakland (ref)
AShbury El Cerrito (ref)
BErkekey Berkeley
ELmhurst Oakland
FRuitvale Oakland
HOlliday Oakland (ref)
HUmboldt Oakland (ref)
LAkeside Oakland
OAkland Oakland
PIedmont Oakland, Piedmont
THornwall Berkeley

Later Exchanges

from 1957 directory

Exchange Areas Numbers
ANdover Fruitvale 26x-
AShberry Berkeley 27x-
CEdar Berkeley 23x-
ELgin San Lorenzo 35x-
GLencourt Oakland 45x-
HIgate Oakland 44x-
KEllog Fruitvale 53x-
LAkehurst Alameda 52x-
LAndscape Berkeley 52x-
LOckhaven Oakland, San Leandro 56x-
NEptune Oakland, Alameda 63x-
OLympic Oakland 65x-
SWeetwood Oakland 79x-
TEmplebar Oakland 83x-
THornwall Berkeley 84x-
TRinidad Oakland, San Leandro 87x-
TWinoaks Oakland 89x-

Links and References