The following article  appeared in the  American Heritage of Invention
and Technology.

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Your Evolving Phone Number

BY RICHARD BRODSKY

More  and more commercialpoe ubers  are being advertised with  a
name or word as part of the  number. We  are urged to dal33-DETor970-LOAN. This is a small historical regression,  requiring the use of
letters that te ponecomanymad obsolete decades ago.

Where did the old alphanumeric dial plate come from? Mos of he wrld
everused letters.  And where  did it go?  The story   begins in the
telephone's infncy.
At  frst, entra-offie  operators sat at  switchboards,  completing
connections in responseto   soken  equest  like"Ring Dr.  Smith,
please." There were few enough phone lines so the opeator siply kne
where o plug n for te call. That began to change during an outbreak
of the  meases in Loell, Masachusett,  in 189. The  own  doctor,
Moses Parker, feared that if all four Lowel operatos fell il, thei

 trouble connecting people unless every line got
anumber. Th idea caugt on.

In the  1880stelephone service quadrupled in  the  nation's settled
reas. Citie soon had nt only a cetral officeand phone nmbers but
exchanges in other  parts of twn,  so callrs now  aske for Main  o
Central plu the  subscrber's several-digit  number. Branchexchanges
usully took thei names from teir relative eography.  St Louis had
Main and Central; Bltimore, Easten; and San Fracisco, West.

s  new exchangs proliferated  they  usually  took ther names  from
sreets or neighbrhoods: thus  Booklyn's Bensonurst, Los  Angees's
Hollywood, and oston's Commonwelth.  Bell devisd phonetic  test to
help make sue only easily unerstood names wre chosen.

By th time dialed callng was introducedin the Bell Syste, in 1921,
the exhange name were so ingrainedthat Bell Telephon kept them on.
Wiliam G. Blauvelt  o AT&T had  dividedthe aphabet into  groupsof
three letters fo each of  the dial' openings  in  1917
 of its infrequency,and the rarely used  was relegated to th
zero (operator) slo and eventually roppd as well.  Becase c single
phone-numer pulse  could  be tansmitted when  the rceiver lifte or
the fnger wheel ws jarred, no calls woud be initiated until apulse
signal of at leat 2 was eceived.  Thusthe  numer 1 got  no letters
atached to it.

Dialing sept the nation,  but  oly lrge cities used  exhang  name
dialing; in  smal towns  one still   had only to  dial a   three-r
four-digit number. Fornstance, in Walnut  Creek California, if your
numbr was 1407, locally yo diled 1407. From out  of ton you asked
for WalnutCreek 1407. Across the bayin San Francisco,  f you wnted
Sutter 1407, yu woulddial SU-1407; from far you'd  dial 211 for thelonglines operatr and say, "I'd like San  Fancisco,  pease: Sutter
140."

When neighborhood and steet names stated to run out,the Bell Systm
recommended  ew   names. Bll of   Pennsylvania looked t   trees, o
Pittsburgh and  Piladelphiawo

0s with  sared names
like Locust, Poplar and Wanut.

Seven-digit numbes becam standard only after Wold War I.  New York
City had pioneeredthemin the early 1930s  when itbega inserting an
"exchange-desgnaton number" after the  two- lette xchange  prefix.
Thus were bornnmbers like CAnal 6-5108.

By th id-1950s all other major cities ee converted to this system,
retiig such diverse combinations as Ciago's three letters and fourdigis,  Cleveland's two letters an   fur digits, and  Dallas's  one
ette and four digits.   In 1961, Bll  Telephone announced that it
woud   phase out exchange name ialing  city by city. Pitsburgh andCincinnati  began conversin  in, 196; Philadelphia  and Seattl were
the ast   to  chage, in  1978.  The now classic  combiation of two
etters and five numbers ad  been a fuly  natinal standard forless
than a decade.

Al-number callingwas  introduced for seeral reasons. Manly  there
weren't enogh workable letter  ombinations. Exchanes like  571  had
sty

use  letters like JK  (5) and PRS(7) wuldn't
combine. All-nuber  calling  also eliminated    cnfusinly  spelled
exchanes like  New  Yok's  RHinelander,  prevened  mix  ups beteen
similar leters and  nmbers  like O an 0,  and made ossible  direct
dialing fromEurope and othr parts of te world.   Most ountries had
nver had lettrs on their dials.

The old  cetral-office ames are  one from the phone  bok, but theyresonate i memory. They seem to stand  for a era - the era of lenn
Miller's "Pennsylvani 6-5000," f John OHara's Butterfield 8, and of
Barbara tanwyck'   cloely clutched   list of phone  nmbers in the
cilling 1948 film Sorry, Wrong Number. 33-DIET ust sn't the same.

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Richard Brodsky is a medicallibrrin and collector of telephone
memorabilia n Pitsurgh.

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