BSTJ 50: 4. April 1971: 1969-70 Connection Survey: Low-Speed Data Transmission Performance on the Switched Telecommunications Network. (Fleming, H.C.; Hutchinson, R.M. Jr.)

10.1 MB·English

1969-70 Connection Survey:

Low-Speed Data Transmission Performance
on the Switched Telecommunications
Network

By H.C, FLEMING an RM IIUECHTNSON. 1.

[Ber stutsiee of lox-perd aturtstop date trazamaaeion over the
Ba Syste © roast metus ae opted tie
rics During the m0-P9 VOI Canevetion Survey, mennivemente
trere made wr 835 snonsctons with gwre 2¢ mallton chevaters trae
tated fo siee en neem aperoge chameter ear ents a Lf 1%
Cher 80 gece of the lonespred feet kts contained wave 3800 or
154000 chovarters A ohartter err sate of 20 or less te inoated
foe 72 per hie a8t pnognt of elle hove w lost
chovatter natant se Bcruatrn pfasinton waitin jor B33
percent of all ull ud BD peoeen! brow na lst characters. Stoities
wok nomen nd carver Jaa d

1 Rees 9 Banauning Lone Sued Data Pexfowanes

“Masearecients of the neruraey 9 Toweapeed da tewsemission ever
the Bel System emizesed networe have heen ined in he 1969-70
‘Tell Com shee he salle wronentee 3s this ete. There

fe widesprend tre of el
Tine evions shal soenouniet

Srp, soonter pets, sn ater ter
‘sane of esta orzannel in har
Scie comriel uf sess i, seis sass ennsmseion rates
tip to BDO ite per sees th/2s, Aso AQMD comin eth Lepr
Nese being uss! ine Ditiehone® service ah the en oF 1970
"Thie aiele pwseats the quant ws) sition of the eharecter
ferro ents coo) Gharasere goeved Anning Hee Tosmanecd kt
‘These yesulis + expe to amet x sew for charasteination ce
svtehed telecomnneations network ior slarbsoy) Uraamiscion of
1395 aun wma sroxese muctneal sounAL, ants 292

low-speed dete. Forthor ancysia of the data is planaed to rinpeine
causes of exzors for whic remedial measures woul be prostable, to
Suggest possible improwemeats in design of eansmision equipment,
sande jncieate possible usefulness of error control systome

‘The measneretta wete plated wih the abjcetive of ekarsetarising
low-speed dava tiazamimion performance aa viowed by user. ‘Tho
rr watstigs ave read for shannels extending fms teanemitting
"un wb nen whic eerste det sghal i at, he pada tthe
eeciving eu at which the charters aye ures oF displayed.

1 Dasign of Seay

‘Detailed planning othe sures ie dserbod in « eowpanion aile
by F. P. Dofy and T, W. Thateher ; « very init summary i pre-
ela es. A randow seston of end pointe for approximately 00
fall calla wan made by mena of a uvee-stage sampliog ln, The
‘rat stage eansstod of division of the 48 contiguous Tritod States
snd Ue provinces of Ontario snd Queber in Cnads inte 12 goo
fraphical areas that originated ronghly equal numbers of completed
fol all Apiary" el ofie wes eat omen fom each ase
wth probably praporsional to the originated fall tafe Tom tal
‘flee, Tn the eeeond wtnge, tro to six calle whieh determined “st.
Chilg" oe arsed tat fice wer sleeve won ym each of toe
rile bade (0-180, 180.725, wi 725 2000 res) relive to ene
rimery offco location, Iho eals rere seleeted from trate printoute
{rom cach primary afer; thor tha ehoaea eeconcary eles hed prob-
ality of select peopeionel to aio originated from. the peinery
fice destined to the secondary oie, ‘The thitd stage eonsited of
‘Gx os more tee calle dieled for: eneh primary ofc to each of ite
fesaciate seenndasy oes, Numerous anelng eraneesion panacsecers
find ereor performance or four Bell Sys dat sels were seaniret
fon most tanretions® Tesults for the Data. Bete 201 (2000 4/4),
20211200 Ws}, cet BOSISACD ame ABI ys} ace cepa yy MED
wlkorie, H.W. Klanee, 8. W. Klare, and W. G. MeGruthen This
rte givee ruts for Duta Set 103 at 150

18 Siar Step Tronamisaion

‘Tae data transmitted at low speed were organized into sucveecve
losbit oherecters, avd were sent ime eatt-etop mode, In tie type of
teanecassion the etcario enn of om iia “etn it vary 0
or specs), followed by seven iofornetion bite used to eneude 128
diferent charectore—alpbabetic, mumerie, punelustion, end vootco
oy 09 mara. euMHOMNANCE, 1387

‘Amorous Siendasd Code for Information Inlerehange, ASCII), fale
‘ore hy 1 parity beck Wit oelectod te give nn even number of uns
for sho information bite and pci Ii, and terminoted by top”
Jnlersal of indefinite duration, ore bit msirasn (binary 1, 7 mar)
Many. terminal viens ane designe to generate und respond to
‘haraorare thus consid

(Character error eteisties, esther than bit eror statistics, are the
pertnctrs of interc n this=xpe of erarenisiny Ieee che messter
funsste of a display Gn leletypewrtrs! or une in computes) of
Carvelers in sot applcasuos, Staetstop texsr‘sien is aseopibe
tor eequences of hardest erro caufed by’ a sluge bib ror. This
froinebeeauce of Ue echanists weed tn iatinguish tho star of a
fuow sharater: the transition Thm a atop interval (mark) to 8 start
Bit tepnoel. A cisturbazee that ovodaeee w pee during s prolong’
top pribe, changes «star Kil (epace) to-a mark this prolonging
{he step pulse, will ece the weviving ceramic te detec ue ets of
the newt chararter at tke wrong poiat is che bi squenoe and to
econ tharaeter ener, This cilition—loss of eluruvier synchroni-
fetion—persies wit the correct inp-rtare trnsition is deseced in
f subsequent charley, Some reciring otuite, for example regen
flrs, have builn algoriteme elt minimize the ressneheonising
Iiuerval Tr ctvorennee, he osseet pesnn Senet aeeidentally as
reall of {he yornletendom eit pstten of tae uu nnssepe. Ta
thor, lose of shiavacteraynebrsating may resus Fen single hit
frror and eaise pronation of ny’ ehsrcctor errors ua elect whieh
net prownl in eynehroneus trnstisson,

2s Tost Arrangement
‘Figur 1 hoes the rest snrangeaent woe fo measure the low-speed
dete transmission performanes, ‘The data were alsa transmit
Irom the sorondary ete beens cmsidorcbly ess exuipment ws ne
fired wo she teanesitting end Wan at the receiving en wih (his
Enrengeren’, atl sts wore eoraueted for two weeks un wre at
primary lovstion eompaed 20 one ve io days at a seeanlary se

tt Temmamiting Bot

A tect seatonee generator (WVKCo OITR) geneeated 9 repeat
spatharsoter fees eemece (FOX sentene) sing ABCTT M-be cher
nwcers at LS charucere per some, er 100 bie, The 72-chanactar
1388 nua amu exernag nucunuent sovamaty axe Lon

Fie 115) be als Ueaon Ul of be 10049 Tul Comesion Survey:

sentence produes the follaviog ne of printing ow a tele-xpmoibe
Zelowed fw dleteshanaesrr, ten on-ingh scent, nd ine Ted
PHE QUICK. BRDWN FOX JUMPED OVW A LAZY DOGS
BACK 12H5a78W0 TESTING, A Lell Sytem 105 ype data we we
thosen forthe Inw-mpend data tranoiaton tts, Thi ae in pina
fof He 100 sci eta wie re we ari leap avid a
in lk Data-Phowe applications, Te uses Srequeney =E'H keying (le
hetmcen IUD ‘spat nnd T2T0 (sarki Sow art ine die
cl tranematson se 2025 (space) aod 2295 (auek) Hs ‘haga bac)
in the other icotion, at rates np 0300 b/s, The 100 dataset as the
‘snanitting sie modulsed the test eentence to @ binary ik signal
at eithr tho lon-bord (F,) or Righ-band (1) frequenties;chece were
‘ternated on seoserve ens

Tie ulyus ipsa power calicgsed to the connection sae between
12 Bin nd 18 «Bor ot Fy and Fy were transmitted at the
same porter, Phere are Ihe values tanually pve x tae ener
ce, In standard installation, ere is sulweribe Loop fom the
tustoner'e proms Uo the pin fonme i teeta efi, Tn the su
vey, the test ectup wie connected ta ke main ‘tame, div incling
4 loo of essontially aor les. Ie nce eosidercé acess te nd
teal loops ta euecomer locate hecsuse loop ahouls ner cegrde he
oow-omngs wirs rhage 1389

evar performane: of 4 eosnertion syiigenty, Mereover, sal los
fine raarmvlom iy oot; Host ist auleeibor statin wes the eae
Ibep fora rll.

sae Roasoing Bd

‘The late ect al We reveiving ete ckinoaated the binery fk
ascend signal to seh! sth or space vllage. The data et com
thine a rvs. rsodulatin disernatne which comsinueus’ makes
line bieaay evry as ve whiter roaring ct spacing frequency is

Sig weve, Tare i 10 tang oF sun yling associate wath Chis
evict.

eat signa! a te out of Le sowiving eeu se ers fre
tue sal at the inp so the eanemting dst set busuuve osm

teins sumsnission characteristics of Ue egzpceion. One
ferunee in diplocenent i tanae of Use work Yo pace sitions
FAourapiesnineion, Tie wae measur iy he distortion wasnring
TAL GNCh MIC) in Pig 1. Rescvin testinal devions differ in cheit
or petiomiance sasecptbiity %0sleyzaph listortion, The st

remgsment invhided a rogenezsier al th ontpet of the seein
{laser wie weer: the legrapa distrtin ron nepigleamounk
Thee fir es, rele apply hw any sersizas asengement tak we
thie Fegeneraos ard toe saleserer a af the Zollowing receiving ir
tus, Wh tals angers, Re rere tea regres ie

Aeteeting reais —rse ber moat? craaals in ese. The sperife
fegenerator er ployod isone need upceal'y wit Une Movdl 37 Tee
ester?

Whe comptes he primary site aterpeled Ube regenerator out

sn tarot nf ASCITsharserere he came mieiner tht teletype
fowl in test insioaees. Te rowsputer seertel and yeronded eur
Foren teseive sv eteor sal cori” Salone iaicaions, whieh owe

‘thee te vrei Se signed level rays to sey Taw vue (appne
Fravely dro lesen
Tae py leslie smnter dueremretod whenecur a reese eee

set Guile pany. fice a kage factor eat 80. yen) of
acters ese horace wa oa Fall vty he prsity ah
Sprott: tle tecere wih a? Samusiate Feceabo uf Rie orewtenne

i eharaeie #00

22 Date Calletion
Taformation identifying eels Tow-spoedt sia teet run a givin
reusuremenls of pari fookie conte and distortion wis wed
1300 sym nnan roman TEENA, JOURKAL, POHL 1601

on log aheste at the pity lestion, Ie mee leo entered nt the
primary site computer by teletyperciter, and thon tranenial erm
Geta Link to computer at Hell Telephone Loboeutries in Tobe,
[New Jersey, where is wae store on maghote tape. The data lik wae 9
tmitehed networieonnestion with transmission seauraey eninead £9
fron detection allele venison.

‘The euowier wh the privacy sie as progranmel lo reo
lnsnebine feo Oke lisesi Hala epeteeatar an eerste hese
ssh the exposted Ciao ts, teak vse oP x FOX serene eh
teat stared in ite memory. Any dseropaney jx the borrowers bis wus
Tbe bolic w share roar teenies eam se Hai
Thi gates) of the reraivee ertnese character ars ie sumer ef

shuaractere reoived sine the Jah, proviusly record. evel

fn ariel eavion, baracler siehnianion way oe Tot ts he
rest of at eoror i arte sa i ssl chosing seera] ane
cessive chraetererrore. Characigr syuebvosiauiion might be recovered
fom the ww chiraeter—n ramition sewmbor oe nee of seen
syuchroniaition. To proven: che computer irom revonding eheratter
furore interminably, when. five ebaranter crore wero dovete! iz #40-
fosian the computer wae eovized te be out e! sontowe eynearonises
TOSS) ead x meyachnonizng gooeacure ees bees, During a2 OSS
ese, a tole soon. 22 tho Bae im al seed chszeetom wee

taken,
The rere! information daseila abo an rear of Mis tne
of oopareener ead datatnn af al cori Talten were Lame
ver the data link to the Hobo computer, This information wae
reoowdid on mngnetie tape, along witli olor low-sp st inr

ison wentigned short and aller snilae information about tbe
igh speed data tests

a Date Prweaing

‘The low-aper cae: seecite wezeapoerarad tron he ether oma
tina am the anngnete tape and ed The wsull sees 4 eonphete
wan of (The hit patter: wal fie of arene eal ebtcueters,
exeep thote remeved by the cliling, spariea oy te pemary te
fomuter [alae eirnsbey evar avd ebacaclers reported Care
(O88 pris) wd (2) the tine of eginning and end of eemrierflune
Jndieitions und OSS conditions

‘Every soit charweter wie eee ae to whether it wae ==
cxived eortety, recived in efor, et aver Ust)—a_cansee
Lon-sr¥M@ ants SUHIDRMANCE 01

ees of came: fll, Tae fist elnraoier a cari fate te
Vlefwsl tn beva charaeler eer, eer Tis wheraeter bs very Wkely to
he teacived fn evar beens of Tone of egal doving the transition
Gf Hie chetaeter A ielelypewiter would very wubably point en ere
for this chavactes, (This definition was necesstry because the pinay
fre compaler il ob ebeek is #aracter for bit ers)

{NSS inersels wens aralyecd as fullons, The wocived characters
report iy te eonaputer wee compared with the FOX aunts har
store Wen the seecrod shares was the FOX eantenee,rhecks
‘iejtnt chacootes detornined wheter senbenoe eye bad wer
feovere, Pas gencelly corral fare te compatereoxple te
Tesyuehronising puvedae, whies was Based on ai fon ofa wei
FOR sentence eharamter Characters vanemiied daring Ut pact of
an O88 interval preeating meovery of sentenee syne were character
fore Stat of Faraecers ols 2eoaecry of =yn9 was hast
fonupaiem with {2 eoreeralmg PON srtonce eaarutet

ingly, ews were panehed er ele call containing ievosation
densify eon sn sting Ute ehacactr trict. Tn edie
tion, the entre eal ae sword vv ewes ina format whieh deseribe
the axaet soqurnee of easier revived comeety, in error, or Ie
‘This infor ‘on wae Fonderse Sy recording Ue length in char
eto) of ittesvale ef roe se ehacseters “et oteh ralegory

‘This a: of eons wpe che ine: ceca from which al er wae
tintin parted fn Une mainder of thie atiela were compte

1 Call Lnluded sn Aalyais

‘The set of rally for which Gata trarsmision etor atstisien ne
repoves in this atbiele fe the ster that for whieh eve sacsies
tee parte (o> The higher! econ data tis esp for esne
fetone cz hil th Jweesee! uid cighspoed deta measures
oul be completed. Bee reasosy'¥en is cexspenion stiles the
eb fers sonal fromm the mt wletel ye the soupling sn ae=
evict easier ‘The exwutial erence ix Use priv offeos ia
the wiz’ ample wove eels hy teas fies, from whieh high

Gagactee cor rts of « ill = rhea elsertes tment Jo
1902 na ana sreness masxouetn sounel, Atm Wet

speed vojoeband date sarc fa that amet would onmully Be atv
1 adaitin, all salle Eaak mene eviteed hy anel type sentra ier
emp ot either end ofthe sonmectinn mete exlued; pam fees
do aot corny serve dala eustouters Cie ma primary offer cone
tines penel eqtipnent, bib leo eaatsine crossbar equicment nd
cone eriganted torough thy Itt cape wee Se

‘42 Stagitude of Low-Sposd Date Saray

‘Toble T aymrnariars the quanttien of gals and pwimary and aeo-
onary heat

"The Gratien of Mawes? dae eel sr seainelly 4 sinates
fesnopt when the 600-4800 Tye dete cet wee net tee for about
Tl? the eas i He fret haf af Me survey). Ta thie ras, the durex
tioa ws aboot gt hour, Exionsent pubes and dropped eonner-
tions eomctimice reelted in shorter rn cule shorter than 23
suinatee, with © aaiimaen of 11 mires, Tv 18 re, eben alate
line was ased for teste longer th: 6 rwinstes, vith = mum
FT ennutes

“Ye IT summarizes tome of the total survey stetstios, Charaeter
eome are chumuetars in which at lest ono fat se reosived im cron
fith che rest that an ertoveaae ehnseeter may be prntec ot en
Tiacested aetion may take place (er exile, cammege tetum) on
‘the receiving teleespewnter. Lost chasucters ate those fo> which no
bie are reosived, usually beoause of lose of Ue toeaved egal
‘resulting in eharactere missing from the celetypewsier pinto. Bt
tition any presented scpanaely dcr these a tyes of “mpc
beceuse they dir in the extent to waioh they damage the come
pieston. Character errors sauy result in neouptaseo of ineorset afar
tation (an ardcr for ene earlaad might be recive as an ovde> for
fine ealoade), whenese los cheractons represent ising iafasaton,
Dereape soquiring vetranenisean of the cee

‘Tama L_C3aa as Lacan Srartsmes

tora [Stor | Medivn Lome
Gol. ee ea
OW SERED BATA HMMORNANCR 1998

‘Vana H—Torat Sonex Cuansorsn Tso axa Tos Cuausuraa.

Sows
“in
coe, tage |g [ratze en gae

Tas sarxins {ina amt Lan ero [sen x ine
Hl |

428 Oval Assy Rate

Overall aserage erar rote ote nln lined in Teble IL. These nr
sei as single Buber paramsers Ut hsrsch~ian te survey. Dis
(vibusiour of por ell estates aro mone sige nant; these zw pees
Inicr wil’s eve, The average exaruterearoreete—eotal chacaoter
errors observed tig the sureay civided by total characters tens
fitted—is 148 10", whieh cartosponste 49 one oer for every 17
Ingo wf wsccip sugested typed fret Ae ig. 2 curve ca). shows
tie erage character er mite we not doniaated by a few bag
tulle itleope Sy a Calor of ey 18 01 3 MPs shan he oh
worse ont

"The average last sharacsr rite 3¢ 881% IP', crrespending to
Jus 27 les characters per ge of set. Tale average tei ly
ominatest iy fe bud walle; omission of Ue eight worst ells which
toninin &3A pertone af the tata ost eselers nproves the averae
Sa feeor of £43 tod, to-47 260" [Tp 2, eurse “BD

oe nucrage chateeter ezor eave bevnes prprrsively poorer as
he mileage howl gels lange, alshous: ts sp ow neeaee is aot
Tas, on'w a fuiue of L8 Last ehaeetee ute t roost inthe shertest

‘rile band, however, omission of wu eatle—the wooet and third
‘worst fara rallsiespyowes che rae i he Lae. bad to 1.55 20%,
‘whieh betes than the mec ara long, un

34 Weighting of Daa fur Celie

Brrr satisee of call nee applieation of weighting fueton vo
rel ull basil er the eee of ie spl proredure by wih
the se: f eal was seeted, Cre eontrilton Ue weigh cng enece
1994 nus am eretine mmcxaess Jovi, AVR TET

for unequal toll tafe oviginsted within the 12 eas inta which tho
riled Stotes aul Carla were divi, A senond sod rah lager
comperent of the wigitiag fuer whi ie applied to she se: of all
cals veeata from large cifeeuece in the fou oll tule frome pri=
ary fo ofes in cach wleage bend A sbird carport is the aetsl
umber of eae for wait low-enced data eror easstice were eOl-
lected bevwaun spose. primary und sealing Inesions. Tn thi
article, weighting was applied oaly wo the evor states of ells pre=
tented in Sertion 3.5 and not tn the ezaining pencmetats, which ate
elated %o tha time eaquenes of oceuronce of ero.

ts Cosmalaie Distributions

‘Figures 34, b, e, sd show weight ecnalative distin for
eavacter cava sate and lost character rate of calls, The anwlghled
Aizibutions fr all calls are chown for comparivon.

‘The carver in Figp. 3 be, wed a Inve fn Welt wrsreothel uo
reflect the actus! resclse ebserved, Tange diventinasiee sometimes
secur when the mumber of ehaructr crors ot lost characters changes
from 0191, 1102, ee

"The wrighted results of erage chargelererorentes (Pig ond bh
for al calle ave closer tothe eeaulte forthe dort mleago bund then

jo