Lucent Technologies DEFINITY Communications System Generic 2.2 And Generic 3 V2 DS1/CEPT1/ISDN PRI Reference Manual

							DEFINITY Communications System Generic 2.2 and Generic 3 V2 
DS1/CEPT1/ISDN PRI Reference  
555-025-107  Issue 1
July 1993
About This Document 
Page xi  
nGeneral Information
This inc lud es DS1 and  CEPT1 c onc ep ts having  relevanc e to field  
p ersonnel. For examp le, it is imp ortant for some field  p ersonnel to 
und erstand  the meaning  of B8ZS line c od ing  in ad d ition to knowing  that 
this op tion exists on the DS1 c irc uit p ac k ad ministration form.
nDesign Details
This inc lud es d etails on how the field -relevant DS1 and  CEPT1 items have 
b een d esig ned  into the systems. For examp le, sinc e line c od ing  has field  
imp ac t (it must b e ad ministered  c orrec tly g iven the transmission fac ilities), 
it is imp ortant to know suc h thing s as the fac t that if ZCS is ad ministered , 
the b it stream on an outgoing ISDN PRI D c hannel is automatic ally 
inverted .
Given these g oals, the d oc ument is org anized  as follows:
nChap ter 1, ‘‘Introd uc tion’’, introd uc es the sub jec ts c overed  in the 
remaind er of the d oc ument.
nChap ter 2, ‘‘Ap p lic ations’’, d esc rib es the various uses for d ig ital trunks in 
the DEFINITY systems.
nChapter 3, ‘‘Equipment and Software Requirements’’, p rovid es ord ering  
information for the equip ment and  software req uired  to imp lement d ig ital 
trunks. It also d esc rib es nec essary c onnec tivity information and hard ware 
switc h setting s.
nChap ter 4, ‘‘Physic al Layer’’, d escrib es how the p hysical layer stand ard s 
of DS1 and  CEPT1 trunks have b een d esig ned  into the DEFINITY systems. 
It also inc lud es g eneral information on these sub jec ts. It c overs these 
top ic s as they relate to narrowb and  (64 kb p s c hannels) switc hing .
nChap ter 5, ‘‘Layers 2 and  3’’, d esc rib es how the layers 2 and  3 p rotoc ols 
for b it-oriented  and  ISDN PRI sig naling  have b een d esigned  into the 
DEFINITY systems. It c overs the sub jec ts found  in the CCITT, AT&T, and  
other spec ific ations, that have relevanc e to p ersonnel imp lementing  d ig ital 
trunks on these systems. It inc lud es g eneral information about these 
subjects and also describes how these subjects have been designed into 
the DEFINITY systems. It c overs these topic s as they relate to narrowb and  
(64 kbp s channels) switc hing .
nChap ter 6, ‘‘System Ad ministration’’, is a g uid e to the p roc ed ures needed  
to ad minister various c ap ab ilities and  features that use d igital trunks. It 
c overs these top ic s as they relate to narrowb and  (64 kb p s c hannels) 
switching .
nAp p end ix A, ‘‘G2 ISDN PRI Imp lementation in Ad ministration’’, is a 
summary of how ISDN PRI has been imp lemented  in G2 ad ministration 
p roc ed ures on a p roc ed ure-b y-p roc ed ure b asis.
nAp p end ix B, ‘‘Dig ital Trunk Ad ministration Summary for U.S. Ap p lic ations’’, 
summarizes some key ad ministration setting s for d igital trunks b ased  on 
their ap p lic ations in the U.S. 
						

							DEFINITY Communications System Generic 2.2 and Generic 3 V2 
DS1/CEPT1/ISDN PRI Reference  
555-025-107  Issue 1
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About This Document 
Page xii  
The following  d oc uments should  b e used  in c onjunc tion with this d oc ument to 
c omp ose a c omp lete referenc e for d ig ital trunks on the DEFINITY systems:
nAT&T DEFINITY Communic ations Systems Wid eb and  Tec hnic al 
Refe ren c e
, 555-230-230
nNetwork and Data Connec tivity Referenc e, 555-025-201
nAT&T DEFINITY Communic ations Systems Generic  1 and  System 75 and  
System 75 XE Feature Desc rip tion
, 555-200-201
nAT&T DEFINITY Communic ations Systems Generic  1.1 Imp lementation, 
555-204-654
nAT&T DEFINITY Communic ations Systems Generic  2 and  System 85 
Feature Desc rip tions
, 555-104-301
nAT&T DEFINITY Communic ations Systems Generic  2.1 Ad ministration 
Procedures
, 555-104-506
nAT&T DEFINITY Communic ations Systems Generic  2.1 Ad ministration of 
Features and  Hard ware
, 555-104-507
nAT&T DEFINITY Communic ations Systems Generic  2.2 Ad ministration 
Procedures
, 555-105-506
nAT&T DEFINITY Communic ations Systems Generic  2.2 Ad ministration of 
Features and  Hard ware
, 555-105-507
nAT&T DEFINITY Communic ations Systems Generic  1 and  Generic  3 
Feature Desc rip tions
, 555-230-201
nAT&T DEFINITY Communic ations Systems Generic  3i\(enGlob al Feature 
Desc rip tions
, 555-230-203
nAT&T DEFINITY Communic ations Systems Generic  3i Imp lementation, 
555-230-650
nAT&T DEFINITY Communic ations Systems Generic  3r Imp lementation, 
555-230-651
nAT&T DEFINITY Communic ations Systems Generic  3i\(enGlob al 
Imp lementation
, 555-230-652
nDig ital Multip lexed  Interface (DMI) Technical Sp ecific ation, selec t c ode 
500-029
nAT&T Tec hnic al Pub lic ation TR62411 ACCUNET T1.5 Servic e Desc rip tion 
and Interface Specification
nAT&T Tec hnic al Pub lic ation TR41458 Sp ec ial Ac c ess Connec tions to the 
AT&T Network for Nodal Service Applications
nAT&T Tec hnic al Pub lic ation TR41449 AT&T ISDN Primary Rate Interfac e 
Sp ec ific ation
nAT&T DEFINITY Line Sid e ISDN Primary Rate Interfac e AT&T Tec hnic al 
Refe ren c e
. This sp ec ific ation is useful for wid eband  switc hing  
ap plic ations. 
						

							DEFINITY Communications System Generic 2.2 and Generic 3 V2 
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nPrivate Branc h Exc hange (PBX) Switc hing  Eq uipment for Voic eb and  
Ap p lic ation, EIA/TIA-464-A
, February 1989. Published  b y Elec tronic s 
Ind ustry Assoc iation, eng ineering  d ep artment, 1722 Eye Street, N.W., 
Washing ton, D.C. 2006.
nAUSTEL (the Australian Stand ard s Institute) TS 014.1/1990, PRI  
Connec tion Volume I: Interfac e Sp ec ific ation for Layers 1,2, and  3
nETSI (the Europ ean Telec om Stand ards Institute) ETS 300102-1, ISDN 
User-Network Interfac e Layer 3 Sp ec ific ation for Basic  Call Control 
Ap p lic ations of CCITT Rec ommend ations Q.930/I.450 and  Q.931/I.451
nNational ISDN Users Forum NIU.302 ISDN PRI for Circ uit Switc hed  Calls
nANSI T1.607, ISDN Circ uit-Switc hed  Call Proc ed ures
nDig ital Ac c ess Sig nalling  Stand ard  II/Dig ital Private Network Signalling  
Stand ard  (DASSII/DPNSS) 
						

							Introduction 
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1Introduction
A d ig ital trunk on a DEFINITY system is a 64 kp b s c hannel, c alled a DS0 c hannel, 
that has b een ad ministered  as a trunk in system ad ministration. This c hannel is 
time-multip lexed  onto a sing le 1.544 mb p s (d ig ital sig nal level 1, or DS1) or 2.048 
mb p s (Europ ean Conferenc e of Postal and  Telec ommunic ations Rate 1, or 
CEPT1) b it stream c arried  on a sing le set of four wires c onnec ted  to a d ig ital 
interfac e c irc uit p ac k. Thus, a DS1 or CEPT1 interfac e c irc uit p ac k p rovid es 24 or 
32 64 kbp s DS0 c hannels resp ec tively, whic h c an b e ad ministered as trunks. 
Conventional analog  trunks would req uire 24 or 32 sets of wires and  several 
c irc uit p ac ks for the same numb er of trunks. In most ap p lic ations of d ig ital trunks 
switc hing  oc c urs at the DS0 level. For examp le, a c all from a telep hone on the 
switc h oc c up ies one rec urring  64 kb ps time slot on the TDM b us and  is switc hed  
to a sing le DS0 c hannel on a DS1 or CEPT1 interfac e that has b een administered  
as a trunk. This is c alled  narrowb and switc hing  and is the foc us of this d oc ument. 
Beg inning  with G3V2, a c all from an end p oint oc c up ying multip le 64 kb ps 
timeslots c an b e switc hed  to multip le DS0s that have b een ad ministered  as 
trunks and  remain in the same seq uenc e as they were when orig inated . In other 
word s, multip le DS0s c an b e switc hed  as a sing le entity. This is c alled  wid eb and  
switc hing . Wid eb and  switc hing allows d ata rates in multip les of 64 kbp s to b e 
switc hed  as sing le entities. For tec hnic al information on wid eb and  switc hing , 
refer to 
AT&T DEFINITY Wid eb and Tec hnic al Referenc e, issue 1, 555-230-230.
At p resent, d ig ital trunks in the DEFINITY systems c onsist of the following :
nTrunks c onnec ted  to d ig ital interfac e c irc uit p ac ks c onforming  to the 
digital signal level 1 (DS1) standard (1.544 mbps)
nTrunks c onnec ted  to d ig ital interfac e c irc uit p ac ks c onforming  to the 
Conferenc e of European Postal and  Telec ommunic ations Rate 1 (CEPT1) 
stand ard  (2.048 mb p s) 
						

							DEFINITY Communications System Generic 2.2 and Generic 3 V2 
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The c ap ab ilities and  features supp orted  b y these trunks vary ac c ord ing  to the 
sig naling  sc hemes they emp loy, inc luding  the following :
nBit-oriented  sig naling , inc lud ing :
— Robbed bit signaling (DS1-only)
— Bit-oriented  c ommon c hannel sig naling
nISDN PRI sig naling, whic h is messag e-oriented c ommon c hannel 
signaling
Based  on these d istinc tions, the following  terms will b e used  in this d oc ument 
when desc rib ing  these different d ig ital trunks:
These trunks have varying  c ap abilities d ep end ing  on the sig naling  used . For 
examp le, if rob b ed  b it sig naling  is used  on a DS1 interfac e, all 24 c hannels on 
the interfac e c an b e used as trunks to c arry voic e or d ata. Bec ause the sig naling  
is rob b ed  from eac h c hannel, however, the maximum amount of information that 
c an b e c arried  b y eac h c hannel is only 56 kb p s. If c ommon c hannel sig naling  is 
used , however, only 23 c hannels c an b e used  as trunks to c arry voic e or d ata, 
the 24th c hannel b eing  exc lusively used  for the sig naling  information. Rob b ed -b it trunk A DS0 c hannel on a DS1 interfac e c irc uit p ac k 
administered for robbed bit signaling and added to a 
trunk g roup .
DS1 Common 
Channel BOS TrunkA DS0 c hannel on a DS1 interfac e c irc uit p ac k 
ad ministered  for c ommon c hannel or 24th c hannel 
sig naling  and  ad ded  to a trunk g roup
CAS Trunk A DS0 c hannel on a CEPT1 interfac e c irc uit pac k 
ad ministered  for c hannel-assoc iated  sig naling  and  
added to a trunk group.
DS1 ISDN PRI Trunk A DS0 c hannel on a DS1 interfac e c irc uit p ac k 
administered for ISDN PRI signaling and added to a 
trunk g roup . Unless it is nec essary to emp hasize the 
CEPT1 or DS1 fac ility, these trunks will b e referred  to 
as ISDN PRI trunks.
CEPT1 ISDN PRI Trunk A DS0 c hannel on a CEPT1 interfac e c irc uit pac k 
administered for ISDN PRI signaling and added to a 
trunk g roup .Unless it is nec essary to emp hasize the 
CEPT1 or DS1 fac ility, these trunks will b e referred  to 
as ISDN PRI trunks. 
						

							DEFINITY Communications System Generic 2.2 and Generic 3 V2 
DS1/CEPT1/ISDN PRI Reference  
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The signaling  information in the 24th c hannel of a DS1 or the 16th c hannel in a 
CEPT1 c an also vary. The simp lest method  is to p rovid e only the b asic  A and B 
b it typ e of sig naling , whic h req uires only one or two b its of information 
(d ep end ing  on the trunk typ e), and  is thus limited  in the amount of information 
that c an be transferred . This is c alled  b it-oriented  c ommon c hannel sig naling . In 
the DS1 stand ard , this typ e of signaling  c an b e either DMI b it-oriented  sig naling  
(DMI-BOS) or AT&T p rop rietary b it-oriented  sig naling . In the CEPT1 stand ard , 
this typ e of sig naling  is c alled  c hannel-assoc iated  sig naling  (CAS).
A more sop histic ated  form of c ommon c hannel sig naling  allows the sig naling  
c hannel to c arry larg e, sop histic ated  messag es, whic h c an c onvey a lot of 
information, suc h as the c alling  p artys numb er, and  muc h more. This typ e of 
signaling is called message-oriented signaling, or DMI-MOS. The only 
messag e-oriented  sig naling  sup p orted  on DS1 and  CEPT1 trunks is ISDN PRI 
signaling. ISDN PRI signaling is message-oriented signaling based on the CCITT 
rec ommend ations Q.921 layer 2 and  Q.931 layer 3 p rotoc ols on the sig naling  (D) 
c hannel.
The following  tab le summarizes the signaling  availab le on DS1 and  CEPT1 
interfac es:
Interface Bit Rate Signaling
DS1 1.544 mb p s Rob b ed  b it
Common c hannel DMI-BOS
Common c hannel AT&T Prop rietary BOS
ISDN PRI
CEPT1 2.048 mb p s CAS b it-oriented
ISDN PRI 
						

							DEFINITY Communications System Generic 2.2 and Generic 3 V2 
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The following  tab le summarizes the DS1/CEPT1 supp ort on the different interfac e 
c irc uit p acks for the various DEFINITY systems:
Imp lementing d ig ital trunks req uires first und erstanding  the req uired  ap p lic ations 
and  then imp lementing  the p artic ular typ es of dig ital trunks to suit the 
ap plic ations. From this p oint, imp lementing  d ig ital trunks req uires the following  
step s:
nOrd ering  servic es or fac ilities, if ap p lic ab le, from the loc al or long  d istanc e 
company
nOrd ering  and  installing eq uipment, suc h as DS1 and  CEPT1 interfac e 
c irc uit p ac ks and  c hannel servic e units, and  setting op tion switc hes on the 
eq uip ment
nOrd ering  sp ec ial software, suc h as ISDN PRI software if req uired .
nAd ministering  the system — this usually c onstitutes the b ulk of the 
imp lementation p roc ess
The remaind er of this d oc ument exp ands on the ab ove subjec ts, p rovid ing  b oth 
the b ac kg round  information and  the d etailed  d esig n and  imp lementation 
information.Interface System Interface Board
DS1 G3iV2 TN722, TN767, TN464 (C or later). The TN722 only 
supports bit-oriented signaling.
G2.2 ANN11 in a trad itional mod ule. Bit oriented sig naling 
only. No ISDN PRI.
ANN35 in a trad itional mod ule. ISDN PRI sig naling  only.
TN722, TN767/TN555 in a universal mod ule. The TN722 
only supp orts b it-oriented  sig naling .
G3rV2 TN722, TN767. Bit oriented  sig naling  only (c an b e used  
for NFAS B c hannels however).
TN464 C or later.
Bit oriented  and  ISDN PRI sig naling. This is the only 
c irc uit p ac k that c an b e used  for an ISDN PRI D 
c hannel.
CEPT1 G3iV2
G3rV2TN464 C or later. The TN464D or later is req uired  for 
ap p lic ations in Belg ium, the Netherland s and  Mexic o. 
						

							Applications 
Page 2-1 Narrowband vs. Wideband Switching 
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DEFINITY Communications System Generic 2.2 and Generic 3 V2 
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2Applications
This c hap ter d isc usses some of the ap p lic ations for d ig ital trunks on DEFINITY 
systems. Applications for digital trunks can be divided into applications requiring 
servic es from the p ub lic  network of the d ifferent c ountries and  p rivate network 
ap plic ations not requiring  p ub lic  network servic es. Within these two c ateg ories, 
some ap p lic ations req uire only trunks with b it-oriented  sig naling  while others 
req uire ISDN PRI sig naling .
Narrowband vs. Wideband Switching
G3V2 systems are the first AT&T p rivate switc hes to offer wid eband  switc hing . 
Until G3V2 all ap p lic ations for trunks, d igital and  analog , were for switc hing  an 
inc oming  64 kb p s c hannel to an outg oing  64 kb p s c hannel. A c all from a voic e 
terminal, for examp le, is c arried  on a sing le 64 kb p s timeslot on the switc hs TDM 
b us. An 8-bit sample is transmitted  8000 times p er sec ond , yield ing  the 64 kb p s 
rate. This typ e of eq uip ment makes c alls g enerating  64 kb p s c hannels when 
d ig itized . This is c alled  narrowb and  switc hing and  is the foc us of this d oc ument.
Ap p lic ations suc h as vid eo transmission req uire more b and wid th than 64 kb p s, 
however. Thus, new eq uip ment c an g enerate c alls at g reater than 64 kb p s. To b e 
c omp atib le with the 64 kb ps timeslots used  in the switc h, however, these c alls 
must b e mad e b y send ing  them on multip le 64 kb ps c hannels that ad here to the 
DS1 or CEPT1 framing  formats (24 or 32 8-b it timeslots). Thus, a c all from one of 
these d evic es must b e at a rate that is a multip le of 64 kb p s. For examp le, a c all 
of 128 kb ps c an b e mad e b y a d evic e that g enerates a DS1 or CEPT1 data 
stream b y p lac ing  that c all on two c ontig uous (c onsec utive) c hannels. These two 
c hannels are then p lac ed  onto the TDM b us in the switc h in the same order and  
within the same frame and  switc hed  to two outg oing  c hannels in the same ord er 
and  in the same frame. It is as if the 64 kb p s c hannels were the c ars of a train 
entering  a switc hyard . The train, whic h rep resents the c all, enters the switc hyard , 
is switc hed  to another trac k, and  leaves the switc hyard  with its c ars following  one  
						

							DEFINITY Communications System Generic 2.2 and Generic 3 V2 
DS1/CEPT1/ISDN PRI Reference  
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Applications 
Page 2-2 Mixed Mode Signaling in G3V2 
2
b ehind  the other in the same ord er as they c ame in. This is wid eb and  switc hing . 
This same analogy applied to narrowband switching would have multiple 
eng ines, eac h rep resenting a c all on a sing le c hannel, entering the switc hyard  
from different trac ks and  leaving  the switc hyard  on d ifferent trac ks. 
One mig ht ask why d oes a single c all have to b e c arried  on sep arate c hannels — 
why not just p ut 100 kbp s, for examp le, on one b it stream and  switc h it 
end -to-end ? The reason is that the TDM b us on the switc h c an work only with 64 
kb p s timeslots. With wid eb and  switc hing , it is up  to the originating and  
terminating end p oints to g enerate the d ata in this format and  to rec eive and  
d ec ip her it in this format.
For d etailed  tec hnic al information on DEFINITY wid eb and  switc hing , see 
AT& T 
DEFINITY Wid eb and  Tec hnic al Referenc e
, issue 1, 555-230-230.
Mixed Mode Signaling in G3V2
Ind ep endent of the ISDN PRI ap p lic ation, G3V2 systems c an sp lit the c hannels 
on a DS1 interfac e b etween trunks using  ISDN PRI signaling  and  trunks using  
rob b ed  b it sig naling . This allows you to d irec t some trunks on an interfac e to one 
d estination and the rest to different d estinations. If all trunks on an interfac e are 
ISDN PRI trunks, they must all terminate at the same destination. For more 
information on how to imp lement this c ap ability, see the sec tion ‘‘G3V2 Signaling 
Imp lementation’’ in Chapter 4, ‘‘Physical Layer’’.
Global Public Network Applications
The telec ommunic ations systems of other c ountries d iffer from that of the U.S. 
and  from eac h other in the ap p lic ations availab le using  d ig ital trunks. Most 
c ountries, for examp le, d o not have sep arate c arriers for long  d istanc e and  loc al 
servic e. Some c ountries offer more servic es than others. At p resent, G3V2 
systems have the c ap ab ility to work with the pub lic  networks in the following  
c ountries, thoug h G3V2 has not b een c ertified  in these c ountries: 
						

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Page 2-3 Public Network Applications in the United States 
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Arg entina
Australia
Belg ium
CIS (Russia)
Czec hoslovakia
Fra nc e
Germany
Greece
Italy
Jap an
Mexico
Netherland s
Saud i Arab ia
Sing ap ore
Sp a i n
United Kingdom
United States
For information on the c urrent state of the servic es ac c essib le via G3V2 in 
c ountries other than the United  States, c onsult your AT&T sales c hannel.
Public Network Applications in the 
United States
In the U.S., the p ub lic  network c onsists of two typ es of servic e p rovid ers, the 
loc al exc hang e c arriers (LECs) and  the Interexc hange Carriers (IXCs). The LECs 
p rovid e servic e to loc ations within a loc al ac c ess and  transp ort area (LATA), 
whic h is virtually equivalent to all loc ations within an area c od e (variations to this 
rule are b eginning  to ap p ear). Comp anies suc h as the Reg ional Bell Op erating  
Comp anies (RBOCs) p rovid e loc al exc hang e servic e. The switc hing  systems in 
LEC c entral offic es p rovid ing  these servic es inc lud e the AT&T 5ESS
® and the 
Northern Telecom DMS® 100, among  others. The IXCs p rovid e servic e b etween 
LATAs, whic h is c ommonly c alled  long  d istanc e servic e. Comp anies p rovid ing  
interexc hang e servic es inc lude AT&T, MCI, and  U.S. Sp rint, among others. 
Switc hing  systems suc h as the AT&T 4ESS
TM and the Northern Telecom DMS® 
250 p rovid e these servic es.
Local Exchange Applications
The servic es g enerally availab le from loc al exc hang e c ompanies in the U.S. are 
as follows:
nDirec t outward  d ial/attend ant c omp leting  inward  d ial
This is often c alled  c entral offic e (CO) servic e. If c onnec ted  to an 
exc hange other than the loc al exc hang e, it is c alled  a foreig n exc hang e 
(FX) service.
nInc oming  and  outg oing  wid e area telec ommunic ation servic e (In-WATS 
and Out-WATS)