Google Groups no longer supports new Usenet posts or subscriptions. Historical content remains viewable.

Dismiss

Operator Toll Dialing and a 1945 Area Code Proposal

60 views

Skip to first unread message

Mark J. Cuccia

unread,

Dec 11, 1996, 3:00:00 AM12/11/96

Early this year, I posted to the Digest an article regarding a
proposed but never adopted area code plan from 1946/47. The proposed
plan was similar to the actual 'finalized' plan of eighty-six original
area codes from October 1947, in that states with *one* area code were
given codes of the N0X format, while states with *multiple* area codes
were given N1X area codes.

In the 1946/47 proposal, the entire country of Canada was 'treated' as
a 'single state' with multiple area codes. The never adopted proposal
would have used codes of the 91X form for Canada's provinces:

912 and 913 for Ontario;
914 and 915 for Quebec;
916 for the Maritime Provinces (New Brunswick, Nova Scotia, Prince Edward
Island; and maybe Newfoundland and Labrador which wasn't actually a part of
Canada, politically at that time);
917 for Manitoba;
918 for Saskatchewan;
919 for Alberta;
910 for British Columbia.

Also, the 1946/47 proposal (but never actually adopted) had
'consecutive blocks' of area codes for each state with multiple codes:
New York State would have had 212, 213, 214, 215, 216
Michigan would have had 217, 218, 219
Illinois would have had 312, 313, 314, 315
Ohio would have had 316, 317, 318, 319
Pennsylvania would have had 412, 413, 414, 415
Wisconsin would have had 416, 417
Minnesota would have had 418, 419
California would have had 512, 513, 514
Massachusetts would have had 515, 516
Iowa would have had 517, 518, 519
Missouri would have had 612, 613
Indiana would have had 615, 616
Kansas would have had 617, 618
Texas would have had 712, 713, 714, 715

I do wonder about Kansas having been assigned (on paper, only) the
codes 617 and 618. I would have thought that it would have been
assigned 618 and 619. Notice that 614 has no assignment, and comes
after Missouri's two codes. If 617 were to be 'skipped' over, it would
be after Indiana's two codes. In the *ACTUAL* assignments of October
1947, MO and IN had two area codes each; 1948/49 saw Indiana get a
third NPA (219) and 1950/51 saw Missouri get a third NPA (417).

Within most (but not all) of these multi-NPA states, the block of
consecutive codes were to be adjacent to one another, or 'linear' as a
code set 'increased' from east to west, or from north to south, across
that state.

Every *other* state (as well as DC) would have had an N0X style area
code, as each of these states would have had one area code.

However, except for the larger cities in multi-NPA states, or more
populated states using a single (N0X) NPA, the numerical assignments
were *not* kept when the finalized version took effect in October
1947.

(The complete chart of 'proposed' assignments with some brief
description of specific intra-state geographies is included in my
original submission, earlier this year).

However, close to the end of World War II, in 1945 the Bell System was
seriously looking into a nationwide numbering plan and developing an
*automated* (operator) toll dialing/switching network.

In August 1943, Philadelphia was the *very first place* to ever have a
crossbar *toll* switching machine, the #4XB Toll switcher. And only a
few years earlier, the first XBTandem switches were installed in the
US:

Detroit's "Trinity" (DTRTMIMD01T) in 10/1941;
Manhattan's "Interzone" (CLLI code not known) in 10/1941;
San Francisco's "Bush-0" (SNFCCA0300T) in 12/1941;
Oakland #1-Cal. (OKLDCA0100T) in 1/1942.

(all of these XBTandems have been replaced by now -- some began to be
replaced with more modern/recent technology beginning in the late
1970's.)

I also have reference to a XBTandem installed in El Monte CA
(ELMNCA0116T) in 3/1940, however the reference source, the Distance
Dialing Co-Ordinating Handbook, AT&T's annual 'toll/tandem switching
inventory', has this in error for the annual editions through
1975. The 1976 through 1981 editions indicate this XBTandem having
been installed in 2/1960. Anyhow, El Monte is in *southern*
California, and in the 1940's and 50's, the Los Angeles and southern
California metropolitan area was a *step-by-step* switching area, and
the other areas having XBTandem in the early 1940's were *panel and
#1XB* local switching areas.

Multifrequency Keypulsing (MFKP) address signalling was being
developed in 1940, to replace revertive pulsing in #1XB local
switches, and was also applied to XBTandem and #4XBToll. Baltimore was
one of the first areas to have an experiment with MFKP between its
#1XB local switches in 1940.

While several operator toll dialing networks had existed on a regional
basis since as far back as the 'teens', they were *regional*, and were
based on Step-by-Step (SxS) switching technology. Dialpulses lose
their effect over longer and longer lines, and have to be
'retransmitted'. It was decided to have the main backbone of a
nationwide automated network to be based on XB and MFKP technology,
which could store and forward digits, as well as translate digits
received.

The ultimate result was to be a standardized numbering plan for
operators (and later customers) to dial/key toll calls. The digits
dialed would be registered, forwarded, and if needed, translated to
localized 0XX/1XX routing prefixes used in any regional SxS toll
dialing networks. 0XX/1XX routing codes have continued to be used for
network routing/control, trunk/equipment testing, and also for
operator-to-operator purposes, even in a "common control" switching
(XB and later ESS/Digital) and MFKP (later CCIS#6 or SS7) signalling
network environment.

Some of the regional SxS (opearator) toll dialing networks which had
been in existance for several decades before WW-II originated from the
*non* connecting competitive independent telephone companies in many
cities and metro areas in the earliest decades of this century. At
that time, Bell was still providing only manual operator handled
connections for local service, while many independents (particularly
the competitive non-connecting ones) had been introducing local dial
services based on Strowger Automatic Electric SxS technology.

Around the time of WW-I, Bell began to study local Panel switching for
the largest metropolitan areas, but it was to have been a *semi-automatic*
service, where the calling party would still have given (quoted to)
the operator the called number, and if the call was in a different
local exchange, the originating operator would dial (or more pecisely,
key-in) the requested number.

By the early 1920's, Panel switching was being adopted by Bell for
local *customer* (and operator) dialing, mostly in the larger metro
areas in the USA only; Bell Canada never did have Panel switching in
Quebec or Ontario). Bell did adopt SxS switching for local dialing
(by both customers and operators), mostly for medium cities, smaller
towns and more rural areas, throughout the USA *and* Canada.

When the non-connecting competitive independents were still quite much
in existance, many began to interconnect their local (Strowger) SxS
dialing networks togather, over a larger region, creating regional SxS
operator toll dialing networks. When the various Bells and competitive
independents began to 'buy-out' each other to create a single
non-competitive connected network in the 'late-teens' and early
1920's, these regional SxS operator toll networks continued, and Bell
began to introduce such networks on its own, or it expanded on what
had already existed from the (previously competitive and
non-connecting) independents.

Some of the larger regions served by SxS (operator) toll dialing
networks prior to the introduction of XBTandem, #4-type XBToll, MFKP
technology:

Southern California (a rather large area of independent telcos);

Connecticut (the "semi" BOC of Southern New England Telephone);

Ohio (another "semi" BOC of Cincinnati Bell Telephone; also several
independents now held by United/Sprint).

Michigan;

The Pacific Northwest - WA/OR/ID/BC/AB (another region where GTE has
been quite dominant, including in Canada; and while Alberta's telco
had been owned by the provincial government and Edmonton's telco had
been owned by the city government, both AGT and Edmonton Telephones
had been purchasing AE Strowger SxS equipment beginning in 'the
teens'.)

{Bell Telephone Magazine} and {Bell Laboratories Record} both had
articles on Operator Toll Dialing in 1945:

"Operator Toll Dialing -- a New Long Distance Method",
{Bell Telephone Magazine} v.22 (1945) #2, pages 101-115 of v.22 (1945)
authors: James J. Pilliod and Harold L. Ryan

"Nationwide Dialing", {Bell Laboratories Record} v.23 (1945) October
issue, pages 368-372 of v.23 (1945) authored by: F. F. Shipley (of the
Switching Engineering Department)

In the {Bell Telephone Magazine} arrticle, there is discussion about a
uniform nationwide numbering plan, with the (continental) US being
divided into sixty to seventy-five areas. Each area would be assigned
a three-digit code, of the N0X and N1X format, as since there are no
letters on the '0' or '1' on the dial, there are no central office
names/letters corresponding to such N0X/N1X codes, but rather
NNX. Thus N0X/N1X area codes would not be in conflict.

In the {Bell Laboratories Record} article, the discussion mentions the
(continental) US being divided into sixty numbering areas, and that
N1X codes would be *tentatively* used, although there are no central
office names/letters corresponding to N0X as well. Incidently, a
sample of a dial is shown in the article, *with* the letter 'Z' on the
'0' (zero), although the article mentions that only eight digits '2'
through '9' are lettered out of the possible ten digits.

The {Bell Labs Record} article did mention that two-digit area codes
'could' be possible if there would be only sixty codes - i.e. less
than one-hundered (or actually eighty) possible numbering areas, but
'NX' codes would make translations between central office codes and
area codes rather difficult until all digits had been received and a
'time-out' in the switching equipment. So, N1X codes would be used.

Both articles include an identical map of the (continental) USA,
divided into numbering areas. Canada is *NOT* indicated on this map,
nor is it even mentioned in the articles. Also, there are *NO* area
code *numericals* shown in each numbering region -- only boundaries.
What *IS* interesting is that there were some area code regions which
would have contained *more* than one state. The caption beneath the
map in the {Bell Telephone Magazine} article states, "How the country
might look when divided into approximately 60 areas for the
nation-wide numbering plan".

The following is a list of each region, as proposed in 1945, using the
two-letter abbreviation for each state. The numbers preceeding the
state(s) is used *ONLY* as a count, and *NOT* any 'proposal' of digits
for each area or region.

01) ME
02) NH *and* VT
03) MA (all) *and* RI
04) CT
05) NY (New York City *as well as* Westchester area *and* Long Island
06) NY State (eastern)
07) NY State (central)
08) NY State (western)
09) NJ
10) PA (eastern) *and* DE
11) PA (central)
12) PA (western)
13) MD *including* DC
14) VA
15) WV
16) OH (eastern)
17) OH (southern)
18) OH (northwestern)
19) MI (southern)
20) MI (northern; panhandle)
21) IN (northern)
22) IN (southern)
23) IL (Chicago area)
24) IL (northern)
25) IL (central)
26) IL (southern)
27) WI (southeastern)
28) WI (remainder)
29) NC *and* SC
30) GA
31) FL
32) KY
33) TN
34) AL
35) MS *and* LA
36) MO (eastern)
37) MO (western)
38) KS (eastern)
39) KS (western)
40) OK
41) AR
42) TX (northeastern)
43) TX (southern)
44) TX (western)
45) MN (southeastern)
46) MN (remainder)
47) IA (eastern)
48) IA (central)
49) IA (western)
50) NE
51) SD
52) ND
53) NM *and* CO
54) AZ, UT, *and* NV
55) WY, MT, *and* ID
56) WA
57) OR
58) CA (northern)
59) CA (central)
60) CA (southern)

One final note -- in the text of the {Bell Telephone Magazine}
article, mention is made that some numbering areas would contain more
than one state, 'such as North and South Dakota'. However, the map
indicates separate area codes for North Dakota and South Dakota, while
according to the map example, North Carolina and South Carolina would
have 'shared' a single area code.

There are also various other articles in {Bell Telephone Magazine} as
well as {Bell System Technical Journal} and {Bell Laboratories Record}
from the late 1940's through the early 1960's regarding Operator Toll
Dialing and how it was evolving into DDD, area codes, local numbering
(i.e. EXchange names and initially how 'standardized' names would be
better for customer quoting and remembering in a nationwide/continentwide
DDD situation, but later how ANC - All Numbering Calling was better),
Crossbar switching, multifrequency keypulsing signalling, etc.

Of course, much of the actual 1945 and 1946/47 area code proposal was
just planning, although eventually was reformatted into the original
'finalized' 1947 assignment scheme of eighty-six area codes, which has
been added on to over the decades, although these current three years
(1995 through 1997), I have identified *at least fifty-eight* "POTS"
(geographic - non-SAC) area codes being assigned and active! Not
counting the SAC's for TWX (N10), the N00's (800 for Toll-Free and 900
for 'mass-calling'), nor the 'patch' codes for access to Mexico, only
thirty-five area codes were assigned (after the original eighty-six
were finalized in 1947) between 1948 and 1965. This remained
relatively stable until the early 1980's. And while a handful of codes
were assigned between 1982 and 1989, even the 1980's was still a
relatively stable period!

0 new messages