Telephone exchange names
A telephone exchange name was a distinguishing and memorable name assigned to a telephone exchange in the early years of telecommunications. In a large city with a linked numbering scheme and many local exchanges, the exchange name identifed the local exchange (central office) in a multi-exchange area. Each local exchange (central office) could have a maximum of 10,000 subscriber lines identified by the last 4 digits of the number; most local exchanges would be smaller but a few locations in the centre of large cities like New York or London could have two or more local exchanges in the one building. The first two or three leading characters of the exchange name formed the first digits of the subscriber telephone number
When automatic dial service was introduced in telephone networks, the leading letters of the exchange names were mapped into digits for dialing. The use of letters on the dial with 3 letters above each digit from 2 to 9, so that the exchange (central office) name could be spelt out by the first 3 digits, was proposed by W. G. Blauvelt of AT&T in 1917.. The mapping was typically displayed directly on the telephone dial by grouping the mapped letters above or around each digit. Several systematic coding schemes for telephone numbers were deployed in varies communities, sometimes evolving over time as the subscriber base outgrew older telephone numbering plans. Widely used numbering plans were systems of using 2 letters from the exchange name plus 5 digits (designated as 2L-5N); or 3 letters from the exchange name plus 4 digits (designated as 3L-4N). For both the 3rd digit was part of the exchange name, not of the local exchange (4-digit) number.
Telephone directories or any other telephone number displays typically listed the telephone number showing the significant letters of the exchange name in bold capital letters, followed by the digits that identified the subscriber line. On the number display on a telephone, the exchange name was typically shown in full, but only the significant letters were capitalized, while the rest of the name was shown in lower case, or as small caps.
Telephone exchange names were slowly abandoned after the introduction of area codes in the United States and other similar all-number calling systems around the world, such as the British all-figure dialling.
United States and Canada 
In the United States, major cities such as New York, Philadelphia, Boston and Chicago first used the 3L-4N system. They were examples of the "big-city" problem, with a large city served by many manual exchanges, which could only be converted to automatic gradually, and necessitating operation with a mixture of manual and automatic exchanges for some years. The Bell System introduced the Panel switch for large metropolitan areas, and by 1950 twenty cities were served by panel equipment. The first panel exchanges were installed in New Jersey (Mulberry & Waverley) in 1915, though they were initially semiautomatic exchanges and the customer asked an operator for the number.
Later the 3L-4N system was replaced it with the so-called 2-5 numbers or 2L-5D, two letters and five digits (though the first 3 digits still identified the local central office). For example, a number on the Pennsylvania exchange would be shown as PEnnsylvania 6-5000. This became the North American standard as customer-dialed long distance service, known as Direct Distance Dialing, came into use in the 1950s.
The standard format for displaying telephone numbers that used exchange names was to capitalize the first few letters that were dialed, for example:
- BALdwin 6828 (typical urban North American before move to two-digit exchange names)
- MArket 7032 (typical urban North American six-digit phone number, phased out in 1950s)
- MUrray Hill 5-9975 (one of the Ricardos' numbers on I Love Lucy. Note that the H in Hill, although not dialed, is still capitalized)
- ENglewood 3-1234 (typical North American, in New Jersey or continent-wide after about 1950)
In print, such as on business cards or in advertisements, the full exchange name was often abbreviated, with a period used to indicate the abbreviated form, an example being:
- TEmpleton 1-6400 would appear as TE 1-6400.
If the letters were not dialed, it was common to capitalize only the first letter of each part of the exchange name (e.g., "Metcalfe 6000" or "Fairmont 3335"). Such numbers could be of non-standard length, simply because they were not dialed, but quoted to an operator who plugged into the appropriate line.
During the 1950s, cities using six-digit numbers migrated to seven-digit dialing. Typically, several six-digit exchanges were co-located in one building already, with new ones added as old ones had filled up. They were then combined into a new seven-digit number exchange.
|2||A B C|
|3||D E F|
|4||G H I|
|5||J K L|
|6||M N O|
|7||P R S|
|8||T U V|
|9||W X Y|
In 1955, AT&T distributed a list of recommended exchange names that were the result of studies to minimize misunderstandings when spoken. There are no exchange names for the number sequences 55x, 57x, 95x and 97x as the mappings for the digits 5, 7 and 9 had no vowels, thus making it difficult finding names with those consonant combinations. As a result, those numbers were originally never assigned to exchanges. On the telephone dial, letters were mapped to digits using the assignments in the table (right).
- 22x: ACademy, BAldwin, CApital, CAstle
- 23x: ADams, BElmont, BEverly, CEdar, CEnter, CEntral
- 24x: CHapel, CHerry, CHestnut, CHurchill, CIrcle
- 25x: ALgonquin, ALpine, BLackburn, CLearbrook, CLearwater, CLifford, CLinton
- 26x: AMherst, ANdrew, COlfax, COlony, COngress
- 27x: BRidge, BRoad(way), BRown(ing), CRestview, CRestwood
- 28x: ATlantic, ATlas, ATwater, ATwood, AVenue, BUtler
- 29x: AXminster, AXtel, CYpress
- 32x: DAvenport, DAvis, EAst(gate), FAculty, FAirfax, FAirview
- 33x: DEerfield, DEwey, EDgewater, EDgewood, EDison, FEderal
- 34x: DIamond, DIckens, FIeldbrook, FIeldstone, FIllmore, FIrestone
- 35x: ELgin, ELliot, ELmwood, FLanders, FLeetwood
- 36x: EMerson, EMpire, ENdicott, FOrest, FOxcroft
- 37x: DRake, DRexel, ESsex, FRanklin, FRontier
- 38x: DUdley, DUnkirk, DUpont, EVergreen, FUlton
- 39x: EXbrook, EXeter, EXport, EXpress
- 42x: GArden, GArfield, HAmilton, HArrison, HAzel
- 43x: GEneral, GEneva, HEmlock, HEmpstead, IDlewood
- 44x: GIbraltor,GIbson, GIlbert, HIckman, HIckory, HIllcrest, HIlltop
- 45x: GLadstone, GLencourt, GLendale, GLenview, GLobe
- 46x: HObart, HOmestead, HOpkins, HOward, INgersoll
- 47x: GRamercy, GRanite, GReenfield, GReenleaf, GReenwood, GRidley, GRover
- 48x: HUbbard, HUdson, HUnter, HUntley, HUxley, IVanhoe
- 49x: GYpsy, HYacinth, HYatt
- 52x: JAckson, LAfayette, LAkeside, LAkeview, LAmbert, LAwrence
- 53x: JEfferson, KEllogg, KEystone, LEhigh, LEnox, LExington
- 54x: KImball, KIngsdale, KIngswood, LIberty, LIncoln, LInden
- 56x: JOhn, JOrdan, LOcust, LOgan, LOwell
- 58x: JUniper, JUno, JUstice, LUdlow, LUther
- 59x: LYceum, LYndhurst, LYnwood, LYric
- 62x: MAdison, MAin, MArket, MAyfair, NAtional
- 63x: MEdford, MElrose, MErcury, NEptune, NEwton, NEwtown
- 64x: MIdway, MIlton, MIssion, MItchell, NIagra
- 65x: OLdfield, OLive, OLiver, OLympia, OLympic
- 66x: MOhawk, MOntrose, MOrris, NOrmandy, NOrth(field)
- 67x: ORange, ORchard, ORegon, ORiole, ORleans, OSborne
- 68x: MUrdock, MUrray, MUseum, MUtual, OVerbrook, OVerland
- 69x: MYrtle, OWen, OXbow, OXford
- 72x: PAlace, PArk(view), PArk(way), RAndolph, RAymond, SAratoga
- 73x: PErshing, REd(field), REd(wood), REgent, REpublic
- 74x: PIlgrim, PIoneer, RIver(side), RIver(view), SHadyside, SHerwood
- 75x: PLateau, PLaza, PLeasant, PLymouth, SKyline
- 76x: POplar, POrter, ROckwell, ROger(s), SOuth(field)
- 77x: PRescott, PResident, PRospect, SPring, SPruce
- 78x: STate, STerling, STillwell, STory, SUffolk, SUnset,
- 79x: PYramid, SWathmore, SWift, SWinburne, SYcamore
- 82x: TAlbot, TAlmadge, TAylor, VAlley, VAndyke
- 83x: TEmple(ton), TEnnyson, TErminal, TErrace, VErnon
- 84x: THornwell, TIlden, VIctor(ia), VIking, VInewood
- 85x: ULrick, ULster, ULysses
- 86x: TOwnsend, UNderhill, UNion, UNiversity, VOlunteer
- 87x: TRemont, TRiangle, TRinity, TRojan, UPtown
- 88x: TUcker, TUlip, TUrner, TUxedo
- 89x: TWilight, TWinbrook, TWining, TWinoaks
- 92x: WAbash, WAlker, WAlnut, WArwick, WAverly
- 93x: WEbster, WEllington, WElls, WEst(more), YEllowstone
- 94x: WHitehall, WHitney, WIlliam(s), WIlson, WIndsor
- 96x: WOodland, WOodlawn, WOodward, WOrth, YOrktown
- 98x: YUkon
- 99x: WYandotte, WYman, WYndown
Fictitious phone numbers starting with 55 used the fictitious exchange name KLondyke (55). The letters Q and Z were never used in the naming system, but Z was often mapped on the telephone dial to the digit 0 (zero).
All-number calling 
As demand for phone service grew in the post-World-War-II period, it was foreseeable that it would exceed the addressing capacity of the existing system of using memorable telephone exchange names as prefixes for telephone numbers. Several letter combinations had no pronounceable or memorable names and could not be used. Several North American area codes were split to enable reuse of numbers. However, as the growth accelerated, the Bell System decided to switch to all-number calling (ANC). This extended the usable numbering plan and only two area code splits became necessary between 1962 and 1981. All-number calling was phased in slowly starting in 1958. Most areas had adopted it fully by the late 1960s, though it did not become universal until the 1980s. The Bell System published and distributed area code handbooks yearly which compiled the towns available for calling using an area code.
The transition was slow in its implementation, taking the better part of the 1970s and even into the early 1980s to complete. Thus, telephone exchange names were still in use with telephone numbers well after the introduction of area codes.
AT&T employed a gradual strategy to ease the transition for customers. Originally, directory listings were printed with the exchange names spelled out in full, e.g.,
- Jones John 123 Anystreet............BUtterfield 5-1212
- Jones John Paul 5 Revolution Rd......ANdrew 3-2368
First stage was to print only the dialed letters:
- Jones John 123 Anystreet....................BU 5-1212
- Jones John Paul 5 Revolution Rd..........AN 3-2368
Second stage was to assign a selected letters combination in communities being converted from five- or fewer dialed digits to seven; no name was associated with the letters:
- Ramsay Betty 12 Connecticut Rd...........LT 1-5225
Third stage was to assign ANC to smaller communities converting to seven-digit numbers.
- Appleby Charles 1210 MacGill Lane.........553-0086
AT&T proceeded to convert existing named exchanges to ANC, starting in smaller communities. No significant opposition arose until conversion began in major cities. In some cities such as San Francisco, opposition was organized; the opposition group in San Francisco was called the Anti Digit Dialing League, of which S. I. Hayakawa was a notable member. The opposition caused AT&T to slow down the conversion process, and names did not totally disappear in major cities until 1978 (New York City). Philadelphia had named exchanges in the Bell of Pennsylvania telephone book as late as 1983, long after AT&T had hoped to complete the conversion. A company in Philadelphia still letters its dump trucks with the DE 3 exchange as of 2009. Also, a company in Kansas City, Missouri still shows commercials using the WE Westport exchange in its phone number.
Bell Canada, Alberta Government Telephones and B.C. Tel completed most conversions of existing numbers during the first half of the 1960s. Typically in larger communities, conversions would be timed with issues of the telephone directory.
For example, in London, Ontario, three conversions took place starting in February 1962 and completing in September 1963. GEneral 2, 3 and 9 were converted first; later GLadstone 1 and 5, and finally GEneral 4 and 8.
An example from Montreal, Quebec, on August 4, 1957:
- WIlbank became WEllington 2
- WEllington became WEllington 3 (a rare example of keeping the exchange name)
- FItzroy became WEllington 5
- GLenview became WEllington 7
- VEndome became DUpont 7
- HEmlock became POntiac 7
- TRenmore became POntiac 8
- HArbour became VIctor 5
- MArquette became VIctor 9
The use of letters in exchange names resulted in the placement of letters on the telephone dial, even outside the areas using the letter/number combinations. Some Canadian areas at first used original letter schemes (notably Calgary, Alberta) until later standardization within North America.
Two of the most notable cities using the first three letters, four digits system, known as 3L-4N, with the 3L digits comprising the first three letters of the (local) exchange name were Paris and London. They are examples of the “big-city” problem, with a large city served by many manual exchanges, which could only be converted to automatic gradually, and necessitating operation with a mixture of manual and automatic exchanges for some years.
Telephone directories showed the first three letters of the exchange in bold caps if all seven digits were to be dialled; for example, a subscriber's number on London's Whitehall exchange was shown thus: "WHItehall 1212" (the number of Scotland Yard).
If the first three letters were in capitals but not bold capitals, eg HAYes 1295, the caller would dial the first three digits (the ABC digits) only, and when connected to Hayes ask the Hayes local operator for the local number (here 1295). Later call indicator working equipment was installed at some manual exchanges so that the caller could dial all seven digits, and the required number would be displayed to the local operator.
In the United Kingdom, the first Director exchange in London, Holburn Tandem, was cutover in 1927; preceded by any necessary changes in the London area, eg changing some exchange names and making all local numbers (4N) 4-digit. As each digit represents three letters the same network cannot have exchanges called BRIxton and CRIcklewood, which both correspond to 274. In smaller director areas some A-digit levels were combined so that local director exchange would only need four or less groups of directors instead of eight. But if (say) A-digit levels 7 and 8 were combined it would not be possible to have both PERivale and TERminus exchanges in the same network.
The other main UK conurbations followed suit, namely Manchester in 1930 (e.g., DEAnsgate 3414, the number for Kendals department store), Birmingham (in 1931), Glasgow (in 1937), and later Liverpool and Edinburgh (c1950).
The standards for converting exchange name letters in Europe varied, notably in the placement of the letters O, Q and Z.
The switchover to all figure dialling began in the UK in 1966 following the successful conversion of telephone numbers in Paris, in 1963, which until then had also used the 3L-4N combinations. For example, POMpadour became 706, LOUvre was 508, and PIGalle was replaced by 744.
Exchange names in popular culture 
George Clooney's character, Jack Taylor, in the movie One Fine Day explains that his mobile number is "PEnnsylvania 3317".
At least four popular songs use old telephone exchanges in their names: "PEnnsylvania 6-5000" (PE 6-5000), recorded by Glenn Miller, "BEechwood 4-5789", by The Marvelettes, "LOnesome 7-7203 by Hawkshaw Hawkins, and "ECho Valley 2-6809" by The Partridge Family. PEnnsylvania 6-5000 was later spoofed in the Bugs Bunny cartoon Transylvania 6-5000.
Comic singer Allan Sherman includes a song, "The Let's All Call Up AT&T and Protest to the President March" on his 1963 album My Son, the Celebrity. In this song he suggests that people take their protest against all-digit dialing straight to the top. After the failure of that proposal the matter evidently remained on Sherman's mind, for in "Down the Drain", on his 1967 album Togetherness, he wistfully asks,
- Where are telephone prefixes?
- Down the drain.
- They've all gone where old Tom Mix is:
- Down the drain.
Satirist Stan Freberg included a sketch on the conversion to all-number calling on his 1966 album "Freberg Underground Show #1" (Capitol Records T/ST-2551), with the song "They Took Away Our Murray Hills."
The Simpsons often shows the title family's number as KL-5 xxxx (it has been quoted differently in various episodes), which follows the convention of using 555 numbers in fictitious TV and film portrayals. In at least one episode, the phone book is shown to have all numbers listed as KLondike 5-xxxx.
Similarly, in Seinfeld the characters often give telephone numbers beginning with KL-5.
The song "Promised Land", written by Chuck Berry and also performed by Elvis Presley, has the Los Angeles operator being asked to connect to Norfolk, Virginia number TIdewater 4-1009 (sung as Tidewater four ten oh nine).
The 2011 video game L.A. Noire uses many references to named exchange numbers in the Los Angeles area. Some numbers are of prime importance to the plot.
In the movie Sorry, Wrong Number, Leona Stevenson (played by Barbara Stanwyck) asked the operator to dial MUrray Hill 3-5097, which is the office phone number of her husband, played by Burt Lancaster.
In a 1970s era "Forgetful Jones" skit on the PBS children's series Sesame Street, Forgetful's wife Clementine uses a manual telephone and asks the operator to connect her to Texarkana 44, obviously not a standard number, but in real life would imply a very small, antiquated rural telephone exchange.
See also 
- A History of Engineering and Science in the Bell System: The Early Years (1875-1925) p578 by M. D. Fagen (editor) & Bell Labs technical staff (1975, Bell Telephone Laboratories)
- Bell System recommended exchange names (MIT source)
- "Customs: Give Me Liberty", TIME Magazine, 1962-07-13, retrieved 2009-11-22
- Common keypads. International and historical assignments of letters to numbers
- Privateline.com Telephone History: EXchange Names
- Telephone EXchange Name Project
- Official listing of Ma Bell's recommended names
- Old London Telephone Exchange Names
- Notes on Nationwide Dialing, AT&T - 1955. Section II Appendix A is a List of Suitable Central Office Names