BSTJ 50: 4. April 1971: 1969-70 Connection Survey: High-Speed Voiceband Data Transmission Performance on the Switched Telecommunications Network. (Balkovic, M.D.; Klancer, H.W.; Klare, S.W.; McGruther, W.G.)

15.5 MB·English

1969-70 Connection Surve

High-Speed Voiechand Data Transmission
Performance on the Switched
Telecommunications Network

By M, b, BALKOVIC, H.W. KLANCER,
nd WG. MeGRUTHER

Maonsit esived Deeb 4170)

5. W. KIARE,

In this article we prsent erttzater uf dt teasamiaion ester por
fermonce of dees nates of 4963, 8999, any and 48t0 be on fe ill
Syatem Switched Tolessnnminerions Network, The somes data was
faloeted ue pat of the 1989-79 Ceanerton Survey conducted by Belk
Tlvientoran, Rerults are based an anccautements seed om arpeosi-
mately 8D tail connections, ated from 12 receiving Uo BY trans
toiling sites Sn the Pied Stet ond Cound. Stowdard Hei System
Dinu onec® ite sete weve sand ka tmnt snd reon the Etat

i af enone pe cll are piven on @ bit, set an blak
iormation is ela presented on the distribution of intervals
between ero, Ube altuetun of ator Burts, aed the nomabes of ears
bn of varinvs sites, Seine Sicunson Se give om error causes
acre for opiratirn at 2000 be
FResvts of erro one wecavreniente
126 und amin bjs expeommetly a2 peveenr of the canis have err
is 0} f erinr ay 20" biter Getler, uaauining om equ member of
Short, mei, on bong-bnut eal ‘Thie represents 6 substontian
Tuprniement of performance in rungoson with sezalts of previont
iowoeya. For aach of the fone data rates tested, 1000-bit block eror
‘tee afte than on ws rue Jor ovary 1% data blocks krunawiteed
tne ashicved on 89 percent 1 tbe pul, Por operation el 4 2,
“nao ease of eros Ha shore to be Space noi

fe that for opoation at

_Dota-Phone servieo ws irr the steed aeewu in 158.
That tin, the nuts of a oes service be grown yap
1380 zane oman arorine cremstean souinest, Al 12

proximately 50 portent er yest, reling inthe eonacetion of over
TOO,000 date tenuinals by 1970, A wise varie of data eyetem sppli-
ation hus evolved with te ed bony tostandhigher speed, autor
‘ic operation, npproved performauaec, ul lower ests

‘Sinec 1060 the everll switeked telecemmmiections meryork has
bo exyenensed suictential geet snd hung, During ts pied
Ue axouul gresth cace of the vamber of mike of voice ehannels
in the neinerk hae boen aposdrate'y 19 perecns, Mors thea half of
the faites in service today fave heen placed in saview since 1050,
“Assompenying this growth hasbeen the introduction af newiy desined
texan sal switching egignnats Taito, the goth of dat
services hae rnoted in data tasmanian eosigerstivs being rete
tos greser exten: inthe avers lesign, operatir, end mesrvemanee 0°
the switehad sensor

‘Since the azcrerk ‘2 undergone censiderablo sbarge sbere is «
see) ‘or eiment information an preformance. Sueh informetion is of
"alu inthe reign of data eystenaincing the dorgn nf medens acd
‘or sont! precedurc. Ir altn of uee is establishing performance
tbjecives ov? in ienuiting ares hese sorviewimavements may
‘ve resin

Ayn af survey eovinehd fa te pat Sp RTT. have provided
fort re al eat sai elacactviates af “he steed
tuber, "The met wilely known ie Ge veport by A. A, Alexander
TM. Gy, un TD. We. Nas whieh together with fllowap report by
FL, Flot anal R. Mori sikeuses ene performance at ane
1200 1/5, Rese uf other iets combats! ab 2000 at 600 y's on the
sited netaare sin have been veparted This erp i intended to
fupplemn nd apace Lat infor ion

"The zeaulte pescoted in fis poser repr: on ata transaieonexror
perfermeneo for operation a 12, 2000, 3000, ev 4M hj, Phe soures
data was enue as pit of « lenge sea eld mewsurenvent program,
fondicted by Bell Labortcories on the Del Syetens Switched Telwon
niuniosions Netrert, The purpnss ofthe abrecy wus to obtain ere

information un we tranemasen eharurterisis of alt Ua conmere
tion, Buphasis was placed exw ditailed ehicueleraation of each tos
fall Ie edacien to high-speed cite trersmissen rsseuremerts =
ported hare, musuromene of aoalggckaanel saructere euch os,
Tequomry resonsa, envelope delay, PAR peak ta average ceo}
Jimpulse and mersage cenit (hackground) noise, nonlinear detrtion
fd phase jiler were includ inthe survey. Resta af Khe meee.
‘ments ste presented ins companion paper by F. Duly and W.
xo maxennseioy 1351

‘Thatcher, r+ Nhe iasuded were ert performance meseuremenis of
“operation at £90 W's, Results of tse tes ae pesented by H.C, Wlen=
ingand RLM. Lseainson

"The sect two setions 0” bis paper Hiscuse the seating plan by
‘whieh set of eange iors was chose, and the epimers spleen.
oto in cary gue te lestiag ol thos eernerione. The sfllowed
bya aisousion af the results ebieh He verde to these major nee~
tions: pron! statins, Sine grain stasis, no! eas of core, Per
fall slatstits fre presente i lca of eurlative distribution Sane
fiona and low w deverninatiow of the percentage of ells exceding &
pttiecte peronanre ievel Is err rate, Burst eave sn block ero
ft informgion presence chs inane. Fine goin statistics give
Informalins an ow treme oeece wilh « ee] igamples ae batet
Tensth, ne tee ep hth, ol tho pnviity of a epeifa umber
of enter in a block of sats, These eatinticsa7e generally corned
Dyer heer of tet ealle snd are presi gs cumulucive debtors
tthe pba of a oroarrence

A insjor eben iee ef the 1969 79 Connestie: Surviy ws abtaiz
celimaes dara Ucnattssion poriormaner ashieved by, Doto-Phone
eviee, A sétrighsioreaed in phaealction te rel bse obpetve i

Ses singling eke trae a testing connections hetween cus-ome?
Toestlone Beesast delaikel Deta-Phone trafic oweoede are not mein
thine, seograpical diyersion was instead achieved Ly e smpling
rucalre based on overt toll ani ‘he resus in am alin
omplientin esace sone Inet iting eouipment 18 not suisble for
Inge sata serve, Phi eq pent wa 00! used coueltent with
the pmiemt practice of proving bighespeo Deca-Phene service. A
firctor omsbleration seu ces re “46: Dae exec er ie eonnee-
tieos rive eee hasie paris: Us Ton hebwsen che suion sel the
Toca! swilehing for, tae sommection between stiteling fies, ad
the fared orp. Perfortaneetssleennined by che overs eellovetd
‘charaiensins. This naples the serenity of atupling Tous ws well 85
the sonnection: betwrsen ofess, Locps sere not inclu! in the hse
feat conner‘nn fer several zens Toop ie dedicated tow pactralar
tation, horfore the vac silly slservet between xeon calla
tiled from ow pr ear loeaion Ye anocher i pximarily oto the
Uiferer, reveewone obtained 9e.xren the switeking ofits. Purtere
tose, loope esa fer aheepeed dle eaensson are eubyeet Uo we
1982 rer sae sven neceIeaL souNMALy APM IT

tif trenanisvon requirenelia? whieh minimize their efeet oa enor
Derformanoe Ths, lle presale! in this paper nelude anly the
tall eoaredtion bapveen local eviehing ofcaz,Soae cleuzcon is giver
fn vem of taste woncice any svoulatnd Ioape

"The laric ehanete hich umssurersente wore mane were dialed
toll carneetione between Boll Sets local ewitebing offs. All teste
twee inate dur che worm busivess ay; a taste were anade at
night or on weekends, Coane Uo the allt weal Ue sme ola
‘that a customer Joop would taasnate

A three-stage sampling plan, ststifi into thoes mileage Sands,
wae used to celeste tame eomictins The ase sampling plan bee
eon dosessed by Duty ans ‘Toatcher’; the procedusee used aze out
Sine blow, with emphasis othe eelestion af ite for high-speed dete
srnneatnion teste

Te fret stego of sirmphag resultod in the clecton of 12 locat
witching ofeee (prism sites). This was dane by subdividing the
United Stats asd Canada ante 12 anvos of apprinately equal ital
riginsting toll uate. Brincey site slelion within tach subiivicio
teas randnin with probaly of soleting an oes peopel ex
oral originating toll sali. Asani! with each ytwary afi,
Terre! luca ufos (escouceay alex) yore ealeted at anslom based
fn toon! of specific tall srafh urginating om the primary sta
Secontary see neve statife: ir Un lege Ie 0-180, 180
1725, and 725 2000 mile sta Irom tbe primey. Sieliention took
place before seeoviary selertinn ta eleain approxinntely. the sampe
ber let eaTl jn ea eye and, A lala] of 82 seendary
tes yur sleeved fa she short mileoge band und 3 see were eleted
in bh he mig ad long ioe ban

Consvieat its he sampling eli, oll test eas were dialed fom
‘the primacy sit to the eran ste The est lan eno forthe eka
foliation af sig Una els Inia each prim nyoaroonlary pair

Accliepsrel exter, snipe obtained ae csveribod kore eodld
teatain heal swing vouisment tht isnot euitable for bigh-rpeed
‘cua traning, For exp, offers with panel wsuipuert and eee
twin equipment atsoeinced with step-by-step (SKS) offers an cans
gh levels of ianpulse noise. In providing Data-Phone ae-view on the
itehee aotwork, tie necescary at nes to byoces euch enipmnen,
‘Thus, the following peoecéares mere need cn seit the snmp

Woon 4 primary ele contsining vanel equipment we wleied, the
rmotsuremente weve mace from sn altemate, resote exenage off,
‘Tae ofee used was that from whieh a high-epee data rasiomer wold
no aneessio8 1388

bye cere if the panel oie in face eaused unsutisfastary ists Exams
mission perfermanee, One pray flee with panel equiprent was
elects ut ik alan eontained exahr sqlpmant. ‘Tos high-speed
Incamurezsnts were wae on che arossbar mgebine. Ip the ens of
Donel scondhrns, tater than testing ah an alternie oe, Ue re
Dus were ol his wer dane Beeauee ti small emaunt of adie
tional precision whieh would have been obtained by vering a xler=
dae dit ao wearont the efor! required, Six scomlary sila were 20
sete

‘When # orimany’afiee contining SKS equipment we encountered,
fnchasion in Uhr staple wee puset on etiafactorly cen the fel
Towing mph wine peetet, ‘Toe sumer of impulce nae wut fa
mirute perils war tieasured at threshold of 69 dilrnC (1 dB.
Ilo the average cceive ca siganl level for aZong-haul ex). "This
‘wes dene for sevrn test lines from tae efee teu hawe the busines
ay: T over $0 porert ofthe lesle exhibited mare than IS noe counts
Aluc to offer minment, the survey sueasuremente were made from the
emote exthange fies, Two sel feat were encounters and the
Eltemaie fines ware esed ge toa les, Te was detersned Hin Le ime
Sule nine in Ue exchies ees ws Laney eaves op wtahes used
fn esect cueing trike, Boone oMl survey test eat ere dialed

tom peng sits to seouary te, this souree 0° be was not a
robe at te eecovny sil, No stondacy oPieee Wit SKS wip
sent were exeiuded.

“The resulting susp used describe high-speed datn neremance
contained 12 jinn efeest sever hal cresbar equipment thee ba
EXB equipment, and two has Hol: erosbar and SNS.‘Thoer were $2
feconcary aes in the espe 6 bail expssba> equipment, 85 had
SX8 equiprent, ae one wae a B38 fice,

"The general test unungenent 8 skown jn Pig, 1 vith emphasis on
to sata Tranarision tess Ae riot on fhe Rue, test word. gert-
tore and dota ee irenitors wrze loeb ul he secondary site. The
hte signe were transsiled to the primary sive where tbe date eet
rescver ar aseeciates te eoipent were lente, Sone af the és
foie ‘were comersed shewh slated suaserye> hes, Also, an
[ntlogdbiyitalroxverter ropes tm eacp.e te rue Tne signal
fone el

A dial toraputer 6 Uho primary site moritoral the mors and
1864 ame ema svorene tmomow. sovRNAL, ARE. ttt

cngrer detector etivity of the dana sacs om @ bit-by-bit ais. Tals
information mae eonpeetad by ube romputer a transite’ aver a
2000 bs daa ak wo Bell sboratries ut Hole, New Foray, were
waa storee om snasnes len “or lar ately, Tos poe te
integrity 0° the test resi, he data fink erp err deletion
wilt blook eeieaieeioa for emer eorecton,

"To provide a eros referme wi the dte Hored on the tapes and
lo prose protetion egainst breakdowns of the main dstsoollection
system, a Buckup eystam es need to eolleet ore saie informatio,
Daring povedy when ese miu cata eolletin eystern was inoperative,
so hilelyshiy information ne eolleeted, However, Uke sucka eystes,
onlingel us eueet biz error rte sformntion,

‘Table Tits dts Set wd rae Une Se aveused i tie
praoer Tuc in the le is information ox tbe least of tat eal
lenglt of the test words used, andl the number of west calla mace a
ach spets In the smplowontation of the 2urvey, the Data Set 208
ws tered ab 9600 b/s at all primary stee wich apprasivately half

H i

ates
scooun verse || eran ene

cpse seen LSoouaree pf oo ar |

{ig ones equpnen ernment for dost te,
Dara masentstow 1385

‘Yanna [Dy See Tuer lsromuntion

to | og | gonmeae | SateeE | Ish
Bie) | Chae! | Test Gs ia | ime
“| 8 7

of he serundary’ sizes. It-was tte ab 4800 b/s Fon the other a
Of ne sernuiary sites ater the 4800 be eplign eeu available,
Approsvita'y Ralf way Uinuygh the suréey. Since this represenss ap~
proximately 25 percent of the tel calls, No informetion is given By
Frleage bard avon fine grain etutisties for operstion xt $800 ys

a Tet Procure

At the beeing of « lst day, te tt ealls ware del from the
primary ste to the sooondazy ee. While anslog transmis nea
Invemesis mero being sce om ome corenlin, voieebaze dtu was
Inaniited an the elle (i, Data transisson oa one exmnection
‘pee at 1200 ane 200 ye, sc or aH mines. On che olhe= conte
fier, t's mere mee at 15D 3% for 4D rinutes ard eller 3600
4806 bys for M0 suinuter Atte the completoe ofthese ty te oles
OF the tos conneotione ware axa) and the provodure peated
fusi al tes had been mace all thewe eaanectiens. Upon empl
ion of this seauenee all lise ree diomnected and thror new eas
were dled ins, nn'an average dn, x cunnections were compa
fisted, There were oPeasios wen sure nf che Tues wore dseonnenied
prematurely; these disonneets rere ususly attebatable to Wsting
tote, Whenerer powstle, another ull sus Tied sd ae many ten
is pore were lr on the replacement

Acitizcurse! ener, measurements woze mee beteen lest site
jing ufioee evi tht nob sods avert loops. To ceteraize the
fecte on dats wel yevfi-wnzee 22 ae diction abroduood by the
movin and ghooe chararteracie af loop, she 1300 and 2000 Is
lata ses were fst tw eersigan bun. Pwo Ate ae receivers of
the sate type were mo consents; une wie eonzeetad exeetly
lithe incoming se sigeal aul the oaher 92 conneesed throug) aa
tnlfvial cable eeeton teptenting 4 pair of subseriter loops. Baki
Invivors were snultaneensls muniored by tbe data eolletion eHio=
1855 vay una wvoneae macatsueat JOURNAL, aa 2

‘ment. Artificial exble sactions representing various combinations of
sverige and wors-enge envlepe del ach lve lope far pate of the
foriber lange” were interevungee. from one test to the nxt, The
3000 vel 4800 y's odesne wore et exten thie eonfiguenion, singe
ly eoniain adaptive cquelzers which cerspersice ier the ele of
fumplitace ani phnse cistorton.

42 Daa Set Tots

‘The data ees wore operated ascersing to standacd Hell Spstem
prvelies, The tranartte lie sigasl as 12 elim the serving,
entra offee, ‘The 1200 ona 2000 be ronivers were operated cing
Compromise cousins the HDD and 4800 be modern end ndeptioe
‘equalizers, The entrier detectors i sll dts ete exe the reese,
ta to be clamped to steady rauring in the event of a earsivr off
indiation, For the dose acts with n reverae ehnel eapahility, the
Date Sete 202 was 205, echo suppressors wore dstble pros t dae

"A peeorandom tet nord wae wird on the digital channel. After the
modems were spneroniaes, the fest wort genenstore were eyncro-
hime acs the cata rerordicg cqupment wus eraled. Por el) cata
ez, 122 data collection equipment zecerced the bit ervor patton
Sd carves fail indiestion en a bic-by-bie base

‘us 1200 bys (Date Se #08)

‘The Data Set 202 employs Srequeney shift keying ta tranmait a
signal an the telephone Ine. Tor the suv, a S1I-bit pscudorsrdom
sword (CCITT Sisadond| wus used as the date souree ot the sseond-
xy ste, AE tho primary sie, lovally generated version of the tot
‘pard wae compared wich the veeived data sigs, and the resulting
fine signed record

‘Thic moder does not provie recive vinsing. The tting saad
ved te aperce the deta onetion ment es recovered rome
det erontings af the Teelved daly hil nan, Aeteble cock reeoeery
yet eas toed ve tnimaige the ogeu=venees of serebronitaien. 3s
Tiesmeen the ceased tase ond ant ie Invally generat sh
flock use! paved ae sali ota ayoehnoray ding
anal inserupsions of up fo ten seconds,

"The Data Set 202 provide a loy-speat soverss channel which wae
aubled during about bl! of the data mae Ae the beginning 0! each
‘0D eet, a tone ma teanarnite! fron rsivn ste to transnit ite la
pene meavasios 1367

Aisa echo suppressere in the eonmeriny and therefore allow simile
faoous fwunssy tranemission, Cn ech Calli was aseertsine whither
ho revere chanel wae operating properly. Failure to receive rever
Channel eneny sas ot! nomi ene set eal

+4 2000 6/8 (Dota 8et 201)

‘Phe Data Sel 201 apo dierceaally ever fons-phace med
latin. hie meiem wa aba lasted wat « 11-bit peeoderandom wun
asthe dita sree

‘The Lita Be 201 piides recover elie which was aod to in-
trp the eosived dala, Thu all essions on errors in the reeived
lala were based on thie rlck sta. Homver sltble clo egen-
frulor was sed with the dats, eullecion equigmeat, Tis eurk wax
‘patie 0° maintsicing synelronis wf uw Ines! word during eae
Anlerrplions of up to ten senna

“To abain sformotion on te ise of transients aoeine the yr
Tortnance of the 2000's waokrn an sul to Mitel converter we
‘ned fo nauple the ne signal rolering the receiver. When bit errs
Deearred i the Tosives dat sizer, ue digital computer reeandel
the corcespoiling syment of tke ine signal, Th this wey, a record
tome sausng events wee aintaired, This enaog ta Higa sure,
{reigns ws imal ae Of the LE primary ies

4.5 S000 and $00 bf (Dota So 2)

‘The Data Set 8 ix snlilevel vestigial wievard AM data ect
whieh osplor® antomtie slaptive cquaLization an echera: detac-
Finn. For thie modkin, ss apsvise star procaiure 3 necezeary to
Achieve spnelronisatinn, This routine we performed at che beeinsing
Gheach Date Set 208 fest, an there were tet calls an which the
‘wnt aul not uchiee ssnelvonisa

"The received timing sil provized by che duuw see was use to
interpret rhe eseived dai Th rar inaintain.syachronisa for st les
fe reed In the abeonee of Bw wigral

"The Dara Set 203 esta ns x serambler to meintoin the setings
ota ateptive equalizer, bo pence Lining reovers ifocmction. et
{wo weep ie signal exergy om re Celapzane. lie eomstart. This
eintler was satel co peoior ho trast bic patra, Th eumsite
fa stage shit regsuer wien peoiees a peeoderandom wort
{phen the Hata snput is eemly spacing At the receive end, a dh=
crembler reverse she prowos. Binante of the structure ef the seme
1388 nye neu aveeme TEeMSTOAL JOURSAL, APREL 171

bler-deseramblar, sm event onthe telashoos ine which causes a single
It error in the sorbed sata results im the recording of three bit
fron The errr patern pried ix
100000000000000000100001

lke ones represent errors, the acrocs reprcont errortroe itt and
‘the lef-com bie i the fi bit delivered his sre eror pagrn b
cxpotiensed in custorer cet curing or ceeurronces. Tae fleet
a the scrambler ill be aot geveral vince in later sections of “hie
aper.

‘The reverse elaanel of he Dais fe 208 we wsed on ll et calls
to send 0 S11 Lt paeidocandesn ward 150 bjs coneurrent with high
seed deta tvenstisio, No mecute wae made of eevese chante]
ror pesformanee. However, presence o? absence of the reverse chan
el signal wae noted. Improper oparstion oecureed in two inctances,

Average bit error rte is te parameter most ofzen sed to deseribe
‘he perfe-mance of a dire! shannel breane itis casy to mensure aod
Je independent of cay partioular data eyscen parameter, sth
black sig Average bis ror rate mse datermied for azch call end is
eeeenle:in Pga. 9, 8, sad 4."Theve figures show cumulative eitiba
‘Hoa funetions (CDife) of the bie error rata per eall tor operation at
1200, 2000, and 600 bys in the short, refi, and lena milewse
strata, "The CDDPe inelngsonrar inrsrred during camir of indieatins
2b dieussed earlier, the outputs of the cata sels are clamped during
‘avrier of indications; heeatee of the randomness of the tet wore
ted 30 percent ormor eatin ia eneanered

Tn onder to teats the sample obtained ro the bace population, the
seondrttion of each tee ell ty chose CIDR is weighty ta prohe
biity of Iueloion n tke semples Figures 2, 8 snd 4 therefore repre=
ent estimates of perfornanee fa: the Datn-Phowe population, They
Aifer only slighty som ha sample dscributions where each tat ell
tnntiiaker ena y ‘Tah IL presente sairiatan ofthe percent o° eto
‘tse ealls ee the tare epeess for 2 thece mileage bens, From Fis.
2, cil gné Tobie TT a roe toward jure perforvanee wih ine
frosing dctance ie event, Hwerer, csee fer soch date et the
etramos ofthe bib errr sate distributions inthe three mileage eato-
{gris overisp, the vorstion within « mileage eotegory ie considerably
‘enter than the difcrenoe Retwoon the categries. The results alzo
Show that error rate perfermanee at 1200 end 2000 bs are eamperahle
‘while error rater 8200 bjs ace somewhst larger.