BSTJ 50: 2. February 1971: The Picturephone System: The Network. (Dorros, Irwin)

7.7 MB·English

‘The Picturephone® System:

The Network

By IRWLN DOLWOS

(Macutiys on? S810)

4 Piturephune® wtaant it abe wasionum advantage of seating
‘aphona equipment. To rove sr, a oe tdeapone twit Be
tablet 6 Pouch-Tans? taephnce Hatt, Video aaa fines oe)
te te ering ented nr srl be prweidwady ional repar e
paive, appropriately equalized. rmnpemanis ae boing provided for
fxtonting PBX and bo teeptene sustoer ewichior araneens t0
fase Piturephone capability. Cental efcvaviehing wile acomplia
Syowssinry vide uiteen under he ota! oj rianry sang acing
Short-haal tn wel be proved on arSinary tank caer enue with
Dnalcens ws far Tags Bangrhaul tena wil make ase of e2:RiM and
Plano mp, sik aitiona’ squint nasted emi af the dina

The netuore wae ceaimed privat jaw foceteloen ntnunioatins,
tt etonal series ae Ding fred as the outa data carson
alae a 20.8 fog angen for acess to aesne't
Caomgnte. her nove mosices ae i he an,

Pielwrephone servi as w slievension to Inepone communi:
cation of ck, This fuve-to-uce cunisuicaion eapabibsy will
be reid 9 taking uainan vantage nf Ube existing netonwide
‘elepione aaoark

“Althea the vantage of sme esate canuaiention betmnen
people wilt Piasophan service i zeadily appacent, the silehel
Pielorepinee sobwork wil he useful in edestinnel wey (Sine
frepbic anicris vl as He drags wl be aeplayes ard highor
fusluien is desir voly soared mnagee wil be tranamited. (2)
‘he ne-ock willbe tae Uy crv sivale with a eompnter High-rpeed
data rill be {zznenitted leven buviness machines in tho meztbit-
pereetond rach {id} Manerer, Pturaphone eerriee will be ued to
omminionie svurig groups 0! people ip conference reers or by 1
222TH ms aver mioUsIONT SOMRNAE, FREMUABE eT

number of ind-idnal pera sl many different lestions. {i ill
vm bo used for surveillanue of events al distant locaticrs. Sone of
‘eve additions uses will be possible adhe wae: of aervio; Ue rest
will core later. "Thexe wil snely be inere applientione, mvc yo to
Ie thought of

“portant a theesedionel uses might become, the Piotuephone
nolo is expected to be used predensnnntly ior foou-Lo-tsce com-
tvniestion in uh uke save way en the velephono network i uzed
predominartly for voiee enmmnnietion. Further, each of the adie
Eonel uses, while imporiaal lo w partoular segment of che mncket,
Fequire ite awa ae: of system paramere to maven the sSstem 20 the
‘pplication est. ave ie nn single ayater, chet wiley all apps
lens of video communication, if enst-uniity fuctors re wnsidered,
Tor thooe reasons, initia, phasis bea boen clare! on decgning the
nonwork for fueatofuce performance, ‘Ike other applieadans were
Teepe in mind and chore ich did nae eerinualy eumpromise the pe
fomanee of the system for feoe-tosace commviniessions have been
sevommodatad,

‘The Pictucephone nctwork wil complement the telephone nebork
‘Vhatie, exiting services il zemain in plaeo; telephones wil enntinas
tbe ese dor seting up eal eur-cialee, apeakerphowe, and cher
cxre telephone foxturce will be reuine!;billig-reeonling proctdurss
vrll zet change; ard enstomore wil chaore between a regular Yoies
Valephone eal and m Pictrephone call wen ny oFiginale 3 ell This
se-called vertical extomion of exiving servives wll lake maxim
indeantage of ovitirg eqvipment

"The fine eustocaers wile froma ‘he busines eurnmunity, This ob-
rervetion has effeted the plisieal deen 0: she Picturaptone Fa
pluoce epovial ersphasa on the tise of enetemer wwitahing eqpipant,
sud guided! the design of tho celaee'y shart neers Tnes laa) which
fonnee’ most busines cantorors with Ue revving enleal ole

The wrfile in this ise cover fhe ital ign ofthe spams of
‘equipmeat thn; will provide Paztrephone sevice. Tunovations thet
srl ed to the initia! eerviee eapelilly are rehiew cor are already in
the design etage and mone are being atsiod. Tulare arioen in this
ownai and elsowhese ill ceurt um new improvements we. hey
‘eng.

"This eatels presenta an overview ofthe aystome; the next attelem
porta on ayetam paramelare sat how they hie some stout be re-
Inainces of th jeeue is orgunized by mejor communicetion system
ngdena! tations, tranaminson, emntral often mwching, customer
swilghing, snd finally, date and computer display equipment
see ween 2

"The meet important adventege of Picfaephone service is that the
mor will be ablo to 4ee-an'Wel as hear the person with sshom be is
talking, Moreuver, (a tzoulate as eloely ac possible Une nacurelnes of
‘face-to-face conversation, th eustomer's hus remain sree as in &
normal eonveration. This fetsre is provided by Uhe addition of
ticrophone and loudspeaker. However, © telephone huadset ean be
tied when sudin privacy ia dered,

“The eauipment required st the eusomer'® lation ia packaged in
Jour parts, thnee of which are shown in Wig. 12 The piesre dieplay
trit contains Bie eamera, pobre tube, loadspenker, and enmplx cle
‘ron to drive theta, A emall contol ped eontsina the user controls
tint the ieopkone, Thege and eny slanlané Toweh-Tore telephone
fire easily antessible in front af tho veer. A cervioe unit containing
the power supply, ogie and contol svi, and tracaminson eual>
ining erulta ie tiounesd out of sight in any location up to 85 feet
‘away, Normal lchling it adequate

"The Powch-Tone telephone in usd for Piturephone service beesust
thera are 12 symbole areileble rather than the 10 eymbols provid by
rotary dine, Tho 12th button, labeled #. in cb lower right-hand ear
her of the Fovel-Tone dal e wed to cerignate 9 Picturophone eal
‘The customer simply deprens (his Botlan and thea, in met cave,
Aine the number of the tatlon he ix calling. No nex mumberin pt
is neoessary, ince the anitching will rogaiza the eymbol nd
ontrol the equipment to ‘mike the video eannection.

Tn cates where telephone company qperator assistance is required
on & Pictucephone eal, the symbol sf is depressed befor the diits
formally wd to reach the operstor. ‘The operate: responds on an
tudowetly basa. An approprinte fx image, however, wll appedr on
‘he eeorner'seocec, Intnl, ie SCT ewitchboard wil be equippo
for Pictursphone operator servoe; the Trafic Service Poti System
(TSPS)* wil be sided Iner. Rewnedad announcements, suck ws 0
uch number or "your eall dda gy through,” will also be provided
fon an auio-only basi.

‘Incoming Pictrephons calle are identified by o distinctive ving
creat by new tobe Fngar in te copay rit. Tf te eustomcr hus
fey teleshone, the key sorespondng wo the called line ighte xed to
esify u Pietuvophone cel ara white fora voice-nly call. Tae call
je normally answered in she hanofree mode by operating w swith
‘on the enslzel pad

"Normally, the Plztwrephono customer eits about three feet away
fron: the eaplay nit, He ee the other person om s 5 % 54 inh
(128 x 140 emt sercen. The images exe displayed BU times per sev
cord. ark sip ey, 0: feae,cotsating of 261 active seanning Tine,
vied ‘nto two ede Te ead linge are fit cig one Bld
and thes she even lines are intesiaeo? in the eysoeding fel. This
teohriqne monkos best use of the one-MILs trenamizeion bandwidth,
eit dvtrbed in dete in the article on ayers etencards*

[Am additional povison peri te igplay of simple graphic ma
esis. A mieoe, bull nly the display un, i digped vali front of
the eaimera Te. Graphic waterial $s plaet! Beneath “hy misoe on
the tableap in Sroat of the aaplay unt end tae earera focuses on
the plane of sho table

"Lines equipped for Pictoeephone wrvive may whee have veioe-oaly
cestensons,eubh as a ecereterys pccup. Althougt video calls eax be

gti sna Spy el, Se and Sree ae
se sarwons 225

answered on such an extension, the euler would wot ee anyone uns
Ue elle pled up on a Picton et

"Pall video service a be supplied ta a PBX attendant if the ems
tomer wishes. As a further option,» fzed imnge, such a8 a company
teen, ean be displayed to the caller while the acbondant handles

all Th ear of thee eiuatona, however, the communication sve

Tes up m fill twoeney viden rien, and bezeo the enstomer wil
‘changed ax Pilucepons rate,
‘Bueincoe comrosnieation eervvon today’ zene from sample direct
tines so sao tample PBX ard Onatrex arangemonts, PIX service
Teatues inchuce diel intercr:tnoriation und aeandantrersee In the
ace of Ceniren, the aervieeloatses inclule direct inward dialing to
Ietopnonee and identified outward dialing, To assure continuetion of
te availabilty of theee existing busines servioes, new Pctusephone
kop telephone unite ofering pickup, hold, and jnlercam service will
be pruvited. Buriness customers whe ourrerty recive thei telephone
anrvie from 701 and 257 PPX®, No, 10 ESS, ar No. 5 crossbar sve
ame, wll be able to aed Poturoplown serve and retain all of tein
major PBX and Cenex featanes Pctarmphone servi with other new
PDX wsierin cne with (se No, 1 TSS spetem wil be insresueet at
A Toter mage ofthe serie.

‘The video signe Iawing the Plturephona service unit of « sation
fs g lue-by-line eloerien] anslag of tho luminance of che sownned
inne interspersed with epproprste horizoninl and vertical synchro-
Ting pals, The igher-frecueney components of the luminance sige
fa ate pee-crphasied to approsimalely match the expedied com
pve note encountered Sn (snemsieion, This technique improves the
Seualeovnoise rio after de-empbasie a the dftant sation. Te pro-
fmplasied too wysform i ilstraed in ig 2

Pistrrphone eervice requzes uo moditeaton to the existing ben
size selene loop: cunveational gall and cho voion portion of Piz
Inrephons walls tao ese ise. Tian adaiona) pits of wise ie
arlacd telephone eabies ene eye forthe vieo siale—one pit
for rapnmission iy each dizelion. To compensnte fos the stienaarion
it sdlea fequencies,equalvers ane Sasa! shout one-mile inte
“os along the nitionel pei. The ON-OFF ewiteh-book signals,
Touche sivling signale and ringing sinuls as well as the votes
portion of Pichurephone ell, 470 Wl tranmitta over the voit pair

"Phe bnsie oval svrengoment for eect lines is shown in Fig. 3
226

yan om ie en a1 po gee om
ae omit A) edn ek aS PT
‘ven serous Br

‘More elaborete malisation arrangemen:s on tho eustomer's premises
are served by similne loop arrangements. For PRX, seh sie-wire
Toop arrangements serve as BX rusk with the vive pair used ex=
thsivly for Picturephoce calle.

Finley, tunes {o disan: ewitehing offces use sie wieee in such
the some fashion, Kor We itil years of sevice, the equalses in
Toops and trunks willbe af the aanie design, Later ew crue equal
faere and loep equslizee, each with inereneed eapsbilties, will be
fvailable, The primary improvement inthe later equalizers wil be che
fapabiliy to wutomalially eompentale for eable transmission vetia-
tions doe to sezaperabre changer. This Wi easy inorenee the de>
tance range of analog transmission in Il area, The milenge rams
tre given nthe artiele on the transmission plan

‘Por trunsrinsion beyond the loos ares, which may initially be a
brurncas dsiiet bat mal, Inter be an entixe metropolitan area, the
tnulog Pietorephone sige] will he encoded in distal wm. Thi tans
orm on invotres eompling at [ae Nyguict reve af about 2 Mite and
then encoding the amplitiies of the diferencer bezecen sucveetive
empl into 8-bie binacy’ codes. "The it rat is thus bout sbx meget
per ovurl "The equipment al one texminal that encodes in one diver
tion end decodes in te othr i alle coder.

Digital trenemission } desirable beotuee exenlily all of sho S-
peinment inthe process ceeors due fo guartistson eros in the ening
End the ecrreponding dhvoing (coding noise). Thnpeinments exn be
enivlled by en appronviate choice of she coding eleeitbm. Once
noodle, the digtel eleva is trerertted, with regontration at aD>
Stonsie‘e poise tn he pata, in sisi s way tat the roveived eoessn is

y LS

Fig Bass lel arengemt
228 mn aes, as

nonely identiel to the srnemited steem regardless of the distance
‘amamitted The digit errors and the timing jitter introduced in
‘anamission are controled eon Uo Inve insgaionnt ee.

A evitebing and transrnicion plan hes hece devisod which limite a
signal n'a compote sornoetion ty 4 singls eeeading an desing to
avoid an aconmufation of culiag aoice, The simal stays in axslog
form in the Toe! ates, Onee encoded for lonzcr-baal tranemisscn, it
stay in digital form unt it secles tho lal ars of the ealed mt
Ton, Thus, the sins sre ewitled in wag form in the loca! azeas
tnd in dial fre in the long-boul plant,

Tn ho inal yours of Pctuemphone wero, voice tod eignaling n-
‘omastion will bo trcamitted on convention earrer-doived volee-
frequency chanacle. Later, as newly developed equipment eniara the
eld, voi and sigualing information wil be cenvertad to digial fora

th the video signal into a corspaive bit

‘The base line rae for encod Pictrsphone signe, with er with
‘oct multisleed voioe and sizuling, is 612 Mb/s The 72 diaitel
ttanemistion lino, sooa to be introduced, tranenite at a 612-Mbyjs
rate andi in fact, the receoa for electing thia partielar signal en-
cofirg rate. The 2 Hine will ncrate up ta several hundrel len
‘ver wre pai aquipped with rogenarcive repeat.

"Digital tramamisson eyatems row being developad fora broad range
‘of eotamunications will ultimately trke over the fong-han lrnsnise
Sion of Plcturephone signee. The frat eyrem to trast! dite bi
Streams Jor long-bet! tanemieecn wil be the TD-2 microwave dio
Inlay spstem. A pals af radio chanzele, one in each dcetion and euch
ving » 20-MHs bandwidth, willbe equipped lo transit 202-Kb/e
serpams eareying three coded Piztoreptone signals. Any or al of the
ten gine of radio channels on a TD.2 aystem may be xo enipped,

‘The LA consis! otble carrier wysiemn will ako fe equipped ta
‘raramit hit ntenns. Ta hie onan, a 13.20-Mbe eetom, comeing te
GSIZ-Nb/ signals, will be traramitied in plase of ove of the sic
‘martezzoups of voioe channels (@U0 rach chinels per mastergzoup|
‘8 par of conve! wits in A enble. Any or laf the rx maeergcours
fm a pair of couxinls may be xo equipped. Thus the TD-2 and L-4
sostenc, aroudy in existence, will mect the lons-hanl reoda of Pzture-
‘hana channels fo the fe few yea

‘The D-2 syetem, solicwiate exeetsor to TDD-2, will als be
capable of carrying the 202-Mbjs pulse steam per radio chsanel. The
T-5 wyeless, now in development, ‘will be oquipped to bandla 12.29
bj pale stron in plate of massergroy, as in the L-4 eystem,
an wara 20

iigher bib rate, ontrying more Pictwphone signals in pace of so¥-
‘ral mastergroups, ur ako contnmplatod en 1-5 for great efceney
Stil later in fim, ober costal eysteae wl a new vege nyster,
ill enry Pichrephons signals wath sll gresteraicieny.

‘Carat research has shun good prospesta for reducing the required
bit ete from 6:12 Mlys to eignfionnli lower ratea hy teking advan
tage of the inkeren trame-tovtrame redundancy. Thies s future
parpert however, and will uot Be svalable in the fin] system,

"The picture that is finally viewed xt x Plstwrephone stain cone
teins impa'rmenteintrodavel by eseh part of the bnik-up eomnerion.
‘The end-to-end impaimente wre controled by holding each part of
the connetion within epic linita. ac of hese a been asigne?
f umereal enl-Loend maximin value with « specifi portion al-
Taare to we one, loops, ranks, ete

tu Joon] costal oe, the vote pit it oonnested to Ue existing
telepbone syileh in the conversions) way. The video pais, however,
trv oonnected to u separate four-wine video ewiteh which i under the
tontul af the existing llerboneewitehing machine

he Prturephone eorvies Bove ofned, No. croabar ewitehing
sunchines wil be motif lo ewiteh video cals with up to © maximum
fof S200 lie eppenrtnces and 400 rank. sppearunces, The eapability
Ut pmviding icturrhone serves will bo adéed to No. 1 ESS later
TPietephone service for eustomnee earved from step-by-sap, pare,
for No. crossbar ofecs willbe rovtel to @ nearby No. erosbar or
Tater, to No, 1 ESS oer

‘Whencvot n enstazer divs x ell, the common conto) equipment
in the switching machine reeogsies the dite ard estabinbes talk-
tng path between the lines ead trunk. Poe voice-oly als the existing
toro" telephone switch makes the vonneeton, When the apecin! pe.
Fagen dialed, indaling 9 Pictsrephore calle calking puth sexe
taslihad theough te tworwire telephone swith, aot a path is estab
The simltacaly frou Une four-ire video site fo the trak
Sle ofthe withing tain. Thar, the audio anc vio paths form &
Compete Fiv-nice appeazance, Ror inte-ofice calls the sixewire Pe
farephowe signal rturge tanh the sitchos vo another line. For olla
toa distant central ofie, Dowever, the path ie established overs six-
trie Piturephune teunk he nudio portion of the aixwire trunk ie
Uaticate wo Piobuephonetanfe end i never unl for voee-ony te
phone tral.
28 tush wet, etme nueumOAL sour, raaMARY md

‘What has been desevibed ahve i the means for avilehing Picture
phone sgaale in ovclg fora, Pietuophoue vigusle wi. be awiiabed in
Us way is the cal cerving eantzel ose. Toll, some of these
une oliccs will alsa provice the toll switching funation, also in
flog form. The digital excoding aud decoding are cazried out within
‘the Sntereie trunks, Later, ce it stmeame WL be mmeeled toll
eaters. Inisally, No. 5 crear systems will funtion a8 the tall eon
ters, and later, oletronie toll switehing machines will aaume this
sunetion

"There ae some esses where i wil be caovomiesTly woenotive to ad
switch remote from the serving central oes. Tue lange business
‘ustomer having a number of Picturephone etstions located few
tales from the serving central ee ie eich en example, In this eae, a
‘wideband remota ewiteb (WERE) esa ba poovided that asta aa 9 con
Cenretor fo reduce the required mumber of video links between the
tustomer and the serving central ofce. Only s partion of the eoxizl
CSreuitry iat tae WBRS, Cortvolereula i the oanteelotfee direct
‘the evitah over zeaua® telephone prs, whieh carve asthe eotro ok.

‘igure + illusivaes tne Pcturepone switching hierarchy. Nove that
‘the tall easter may viteh cither analog or digital signals. Actually,
although not ekown, 2 tll center or a primary cextr may be equipped
to switch kath anslog end digitel sguals in seperate switch matries,
swith codsce in the Saterwitch pathe, The choice ia based on local
‘ranking needs and eeccomice. Figure 4 alzo lustre: a uso of a
WBRS end a rireé-throvgh connection at a cal telephone ond
fico not equipped for Picturaphone ewishing. Although not shows,
fronks may exist between exy pair of switching offes inthe diagram
(except chat the WLIRS oonaceta oxy to it homing ofc)

‘An illustrative lecel s2¢a cootguration ie ahora ia Fig. 5. Anslog
Japa and trurke era shown with lea sad toll enalog ewitebing. Also
shown is bow they interlace with digital trunks end bitstream switch
ig

Pletwrephoxe service wil provide a one-MHs evitzhed network,
woh 8° he capable of proving moze than "eee-a#-youtalk” com-
iunieatioas, Two obvious and importeat additional eapabiities are
‘ing impleronted from the tart: digital deta transmission end intor-
olin Witt w oom.

Tor intial serve, th Pstureyhone networe wil

I tranemit and ro-