The following article appeared in the American Heritage of Invention and Technology. ************** 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. ***************** Richard Brodsky is a medicallibrrin and collector of telephone memorabilia n Pitsurgh. ****************