Lucent Technologies 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
Equipment and Software Requirements 
Page 3-12 ESF T1 Channel Service Unit 
3
— SW6-6 set to op en
— SW6-7 set to c losed
— .SW6-8 set to op en
nFor a d istanc e from 500 feet to 655 feet, switc hes SW6-1 throug h SW6-8 
should  b e set as follows:
— SW6-1 set to op en
— SW6-2 set to c losed
— SW6-3 set to op en
— SW6-4 set to c losed
— SW6-5 set to op en
— SW6-6 set to c losed
— SW6-7 set to op en
— SW6-8 set to op en
ESF T1 CSU Artificial Line Option Settings
Set the XMT (artific ial line op tion) switc h as follows:
n0 d B if the network interfac e is an 8-p in jac k
n15 d B if the d istanc e to the nearest fac ility rep eater is b etween 2000 and 
3000 feet
n7.5 d B for a d istanc e of 1000 to 2000 feet
n0 d B for a d istanc e of 0 to 1000 feet
The fac ility p rovid er is ob lig ated  to p rovid e you with the d istanc e to the nearest 
rep eater. If you c annot g et this information, you c an measure the T1 sig nal level 
to d etermine the c orrec t XMT op tion setting . This req uires a T1 test set. The 
following  table shows the c orrec t setting s b ased  on the T1 sig nal level: 
						

							DEFINITY Communications System Generic 2.2 and Generic 3 V2 
DS1/CEPT1/ISDN PRI Reference  
555-025-107  Issue 1
July 1993
Equipment and Software Requirements 
Page 3-13 ESF T1 Channel Service Unit 
3
Other ESF T1 CSU Settings
Following  are add itional ESF T1 CSU switc h setting s:
nLeave the unit memory add ress c od e alarm op tion (roc ker switc h SW1) to 
the d efault (fac tory) setting . This switc h allows ESF d iag nostic  test sets to 
ad dress up  to 256 ESF T1 CSUs. This switc h d oes not have to b e set 
unless you are using  d iag nostic s and  testing  more than one CSU in a 
network.
nLeave the BER threshold  alarm op tion (roc ker switc h SW2) in its d efault 
setting .
n.Leave the transp arenc y op tion (strap op tion W1) in its d efault setting  (not 
installed). This switc h is used  to ac c ommod ate old er T1-typ e DTEs that 
send  unframed  b it streams.
nOp tion the CSU for loc al p ower d ry loop .
Smart Jacks
Smart jac k is the c ommon term used for the loop b ac k units installed  by the T1 
fac ility provid ers at the network interfac e to whic h the CSU is c onnec ted . They 
are b ec oming  muc h more c ommon and  should  b ec ome the stand ard  network 
interfac e in the future. Following  is an artic le exc erp ted  from the July 1989 
AT& T 
NTO Tec hnic al Monthly
 desc rib ing  the Westell loop b ac k units:
With the introd uc tion of the Westell typ e smart jac ks b y some fac ility p rovid ers, 
there has b een some c onfusion that results in long  installation and  troub le 
learning  intervals. Inc lud ed  here are some fac ts ab out the Westell T1 Fac ility T1 VoltageCable Length in 
Feet to Nearest 
Repeater (22 gauge) CSU Setting
<  1.68 >  3000 feet The CSU is loc ated  
too far from the 
nearest rep eater.
1.68 3000 15 dB
2.03 2500 7.5 d B
2.47 2000 7.5 d B
3.05 1500 7.5 d B
3.76 1000 0 d B
4.51 500 0 dB
>  4.51 <  500 0 d B 
						

							DEFINITY Communications System Generic 2.2 and Generic 3 V2 
DS1/CEPT1/ISDN PRI Reference  
555-025-107  Issue 1
July 1993
Equipment and Software Requirements 
Page 3-14 CEPT1 Channel Service Unit 
3
Loop b ac k Units. There are two b asic  families of these jac ks, the 3100-XX and  
3101-XX series. Eac h family c ontains 16 versions of the jac k. The only d ifferenc e 
in the two families are the loop b ac k ac tivate and d eac tivate c od es. The 3100-XX 
series has a 5 d ig it c od e, 11000 to ac tivate and  11100 to d eac tivate. The 
3101-XX series has a 4 d ig it loop b ac k c od e, 1100 to ac tivate and  1110 to 
d eac tivate. The reason for 16 versions of eac h series is to provid e c omb inations 
of four options:
1. DC loop b ac k ab ility
2. Shorting  or non shorting  c ustomer interfac e jac ks (RJ48)
3. Loc al p owering
4. Bantam jac ks and  terminations for ord er wire and  fault loc ate p airs
These units are eq uip p ed with LBO c irc uitry for 0d B, 7.5d B and  15d B whic h 
allows us to set our CSUs for zero and  have the owner of the fac ility make the 
p rop er ad justments. Where these units are p roperly installed  there should b e no 
more g uessing  ab out the d istanc e to the last rep eater!
The units have a b uilt in 8-p in mini-mod ular c onnec tor. The rec eive tip  and ring  
are on p ins 2 and  1 and  the transmit tip  and  ring  are on p ins 5 and  4. This 
c onfig uration c onforms to TR 62411 DEC 1988, FCC Part 68 and  ANSI T1E1 for 
RJ48C and  RJ48X jac ks. There is one exc ep tion to this and it is a unit c od ed  
3101-00. The transmit tip  ring  of this unit are on pins 8 and  1 and  the rec eive tip  
and  ring are on p ins 5 and  4. This unit c onforms to the old  PUB 62411, OCT 
1985, in referenc e to the ISDN stand ard  for an 8 p in mini-mod ular c onnec tor. 
Westell states that this is the first unit they made and it was b uilt to sp ec ific ations 
p rovid ed  b y a c ustomer.
In most c ases the fac ility p rovid er will op tion the ab ove units to loop (switc h 4) 
the sp an p ower. This will allow them to p ower the unit from the sp an and  p rovid e 
sealing  c urrent in the fac ility segment to the c ustomer premises b ut avoid  
resenting  hazard ous p otentials on the c ustomer sid e of the network interfac e.
CEPT1 Channel Service Unit
Most c ountries p rovid ing  E1 servic e p rovide the CSU func tion as p art of the 
c entral offic e. Other c ountries d o not have any p ublic  network servic es. In these 
c ases, the c ustomer must sup p ly the CSU. Presently, AT&T uses the numb er 8 
TR631 Dig ital Line Unit, p rovid ed  b y AT&T Network Systems International for 
these 2.048 mb p s CSU ap p lic ations. 
						

							DEFINITY Communications System Generic 2.2 and Generic 3 V2 
DS1/CEPT1/ISDN PRI Reference  
555-025-107  Issue 1
July 1993
Equipment and Software Requirements 
Page 3-15 Multiplexers and Other Customer Premises Equipment 
3
Multiplexers and Other Customer 
Premises Equipment
NOTE:
Equip ment suc h as T1 multip lexers, b it c omp ression multip lexers, and  
ec ho c anc ellers c an c orrup t the DS1/CEPT1 b it stream. This is esp ec ially 
true of ec ho c anc ellers. Some T1 multiplexers, for examp le, have b uilt-in 
ec ho c anc ellers that will c orrup t the b it stream. Thus, if you are have 
p rob lems isolating a p rob lem with estab lishing  an ISDN PRI D c hannel link, 
c hec k to see if any of these typ es of eq uip ment are in the c irc uit. 
						

							Physical Layer 
Page 4-1 Bit Rate 
4
DEFINITY Communications System Generic 2.2 and Generic 3 V2 
DS1/CEPT1/ISDN PRI Reference  
555-025-107  Issue 1
July 1993
4
4Physical Layer
This c hap ter d isc usses how various asp ec ts of the p hysic al layer p rotoc ols for 
DS1 and  CEPT1 trunks have b een d esig ned  into the DEFINITY systems. It 
d isc usses these sub jec ts as they relate to narrowband  (64 kb p s) switc hing .
For tec hnic al information on wid eb and  switc hing  in DEFINITY systems, refer to 
AT&T DEFINITY Wid eband  Tec hnic al Referenc e, issue 1, 555-230-230.
In the c ases where a relationship  exists, this c hap ter d isc usses how p hysic al 
layer sub jec ts relate to system ad ministration. For a c omp lete g uid e to 
ad ministering  narrowb and  DS1 and  CEPT1 c ap ab ilities, however, you should 
refer to Chap ter 6, ‘‘System Ad ministration’’
. The physical layer aspects of digital 
trunks on the DEFINITY systems inc lud e those sub jec ts involved  with transmitting  
b its from one DS1/CEPT1 interfac e to the far-end  interfac e. Many func tions of the 
p hysic al layer are g overned  b y ad ministration op tions in the DEFINITY systems. 
This c hap ter c overs those sub jec ts.
Bit Rate
Bit rate is the numb er of b its p er sec ond  transmitted  b y a d ig ital fac ility interfac e 
c irc uit p ac k. DEFINITY systems sup p ort two d ig ital trunk bit rates, DS1 (d ig ital 
sig nal level 1) and  CEPT1 (Conferenc e of Europ ean Postal and  
Telec ommunic ations Rate 1). The DS1 rate is 1.544 mb p s. The CEPT1 rate is 
2.048 mb p s.
G2.2 sup p orts the DS1 rate only. G3V2 sup p orts both the DS1 and  the CEPT1 
rates on the TN464C or later DS1/CEPT1 b oard . 
						

							DEFINITY Communications System Generic 2.2 and Generic 3 V2 
DS1/CEPT1/ISDN PRI Reference  
555-025-107  Issue 1
July 1993
Physical Layer 
Page 4-2 Framing Format 
4
G2.2 Bit Rate Implementation
No spec ial ad ministration is required  to imp lement the b it rate in these systems.
G3V2 Bit Rate Implementation
To imp lement the d esired b it rate in G3V2 you must d o the following :
nDetermine the req uired  b it rate for your ap p lic ation. For examp le, you 
mig ht b e c onnec ting  to the pub lic  network in a c ountry that sup ports only 
the CEPT1 b it rate. You mig ht, on the other hand , b e d irec tly c onnec ting  to 
another DEFINITY system in which case you could c hoose to use the 
either the DS1 rate or the CEPT1 rate. Both end s of the interfac e must use 
the same rate.
nYou must have a TN464C or later to imp lement the CEPT1 b it rate. You 
must have a TN464C or later or a TN767 or a TN722 to imp lement the DS1 
b it rate.
nEnter the c orrec t op tion in the DS1 c irc uit p ac k form in the Bit Rate
 field .
NOTE:
The title of the DS1 c irc uit p ac k form is mislead ing  b ec ause it is used  
to ad minister b oth DS1 and  CEPT1 c irc uit p ac ks.
nSet the b it rate jump er on the TN464C to the c orrec t rate.
NOTE:
A system c an c onsist of b oth DS1 and  CEPT1 interfac es. Thus, a c all 
inc oming  on a CEPT1 fac ility c an b e switc hed  to a trunk on a DS1 fac ility 
and  vic e versa.
Framing Format
Framing  is a c onc ep t c ommon to b oth DS1 and  CEPT1 stand ard s, thoug h they 
d iffer in how they imp lement framing . A frame is the set of 24 (DS1) or 32 (CEPT1) 
8-b it time slots that is treated  as a sing le transmission unit.
Eac h CEPT1 frame has 32 time slots. Eac h DS1 frame has 24 time slots, plus 1 
b it, known as the framing  bit, that is inserted  at the b eg inning  of eac h frame.
Sinc e eac h frame rep eats time slots in the same seq uenc e as previous frames, 
the time slots rep resenting  a sing le c onversation or d ata stream form a DS0 
c hannel. 
DS1 b oards sup p ort two framing  formats, selec tab le throug h system 
ad ministration, the D4 sup erframe (also c alled  D4 framing ) and the extend ed 
sup erframe (ESF). The ESF format is p referred  b ec ause of its sup erior reliab ility.  
						

							DEFINITY Communications System Generic 2.2 and Generic 3 V2 
DS1/CEPT1/ISDN PRI Reference  
555-025-107  Issue 1
July 1993
Physical Layer 
Page 4-3 Framing Format 
4
However, either the superframe or the extend ed  sup erframe format may b e 
c hosen; the d ec ision must d epend  on the network eq uipment and  ap p lic ation.
The framing  format does not p lac e any req uirement on the typ e of sig naling  or 
line c od ing  to b e used . However, the type of framing  used  at b oth end s of the 
transmission fac ility must b e id entic al, unless the sig naling  and framing  are 
c onverted  somewhere in the transmission stream (as mig ht happ en in 
international c ommunic ation).
The DS1 Superframe 
A sync hronization p attern is a c ontinuously repeating  string  that orients the 
rec eiving  end  to a frame’s b ound aries d uring a transmission. The DS1 
sup erframe, formerly c alled  the D4 frame, uses a 12-b it fixed  sync hronization 
p attern (100011011100). This 12-bit p attern is formed  b y the framing  b it (the first 
b it) from 12 c onsec utive frames. When the rec eiving  port finds the p attern ac ross 
the frames, it c oinc id entally has found  the b ound aries of eac h frame, b ec ause 
the framing  b it marks a frame’s b eg inning  and end . The 12-frame unit that 
c ontains the sync hronization p attern is known as the 
sup erframe. 
						

							DEFINITY Communications System Generic 2.2 and Generic 3 V2 
DS1/CEPT1/ISDN PRI Reference  
555-025-107  Issue 1
July 1993
Physical Layer 
Page 4-4 Framing Format 
4
Figure 4-1. DS1 Superframe Format
DS1 ESF Framing
The ESF framing  format was d evelop ed  after the sup erframe format. Not all 
eq uip ment used  with the DS1 interfac e sup p orts ESF. Sp ec ific ally, most D4 
c hannel b anks (unless they are c onfigured  as LIU-3ESF or eq uivalent) and  
CDMs d o not c urrently sup port ESF framing .
cydfds1f RPY 060597
FT
FS
F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12 Command F1
11111 111
111 0
0
000 0 00000011
Fr ame #1 Superframe = 12 Frames
1.5 MS. 2316 Bits
1Frame
125 SEC 193 Bitsm
1
12345678 12345678 12345678
F224Time
Slot #
Bit #
Fr ame
#F d1d2d3d4d5d6d7d8
1
2
3
4
5
6
7
8
9
10
11
121
0
0
0
1
1
0
1
1
1
0
0X
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
X
X
X
X
X
X
XX
X
X
X
X
A
X
X
X
X
X
BA signaling frame
(optional with robbed-bit signaling)
B signaling frame
(optional with robbed-bit signaling) 
						

							DEFINITY Communications System Generic 2.2 and Generic 3 V2 
DS1/CEPT1/ISDN PRI Reference  
555-025-107  Issue 1
July 1993
Physical Layer 
Page 4-5 Framing Format 
4
Figure 4-2. The Extended Super Frame
The sync hronization p attern for the ESF format is formed  b y the framing  b it from 
24 c onsec utive frames. Unlike the 12-b it sync hronization p attern for D4, whic h 
utilizes all of the availab le framing  b its for sync hronization, ESF emp loys only 6 of 
the availab le 24 framing  b its to c arry a sync hronization p attern. The other 18 
framing  b its form a 6-b it error-d etec tion c od e, c alled  the 
cyclic redundancy 
c hec k
 (CRC) sum, and  a 12-b it fac ility d ata link sig nal. Eac h 24-frame entity, 
sp anning  one ESF c yc le, is referred  to as an 
ESF s u p e r f r a m e.
cydfesfr RPY 060597
Fr ame
number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
248-Bits
8-Bits
8-Bits
8-Bits
8-Bits
7-Bits
8-Bits
8-Bits
8-Bits
8-Bits
8-Bits
7-Bits
8-Bits
8-Bits
8-Bits
8-Bits
8-Bits
7-Bits
8-Bits
8-Bits
8-Bits
8-Bits
8-Bits
7-Bits Data link F bit (DL)
CRC-6 F bit
Data link signal
Frame sync pattern
Data link signal
CRC-6 F bit
Data link signal
Frame sync pattern
Data link signal
CRC-6 F bit
Data link signal
Frame sync pattern
Data link signal
CRC-6 F bit
Data link signal
Frame sync pattern
Data link signal
CRC-6 F bit
Data link signal
Frame sync pattern
Data link signal
CRC-6 F bit
Data link signal
Frame sync patternFr ame bi t
definitionsFr a me b i t
Channel 1 Channel 2
0
0
0 1
1
1 D Robbed bit (optional
)
C Robbed bit (optional)
B Robbed bit (optional)
A Robbed bit (optional) 
						

							DEFINITY Communications System Generic 2.2 and Generic 3 V2 
DS1/CEPT1/ISDN PRI Reference  
555-025-107  Issue 1
July 1993
Physical Layer 
Page 4-6 Framing Format 
4
NOTE:
The fac ility d ata link is a 4-kb p s d ata link d esig ned  to maintain and  
sup ervise the DS1 fac ility. However, this 4-kb p s d ata link is not used  b y 
DEFINITY systems.
The CRC is used  at the rec eiving  end  to d etec t transmission errors, as follows: 
The CRC is c alc ulated  at the transmitting  end  and  multip lexed  into the DS1. At 
the rec eiving  end , the CRC is rec alc ulated  using  the d ata in the rec eived  ESF 
sup erframe and  then c omp ared  with the rec eived  CRC. If the rec alc ulated  CRC 
and  rec eived  CRC d o not matc h, a 
misframe is d ec lared . The DS1 interfac e 
c ounts misframes and  uses the c ount for p roc essing  DS1 fac ility p erformanc e 
ind ic ators, suc h as b it-error rates, major alarms, and  minor alarms.
The ESF reframing  alg orithm c an find  the sync hronization p attern even if the time 
slots for the 24 c hannels c arry a b it seq uenc e identic al to it.
CEPT1 Framing
CEPT1 framing  is used on 2.048 mb p s CEPT1 32-c hannel (0-31) links. It is 
sup p orted  only on G3V2 systems on the TN464C or later. With CEPT1 framing , 
the 0 c hannel c ontains all the framing  information. With CEPT1 framing, the 
framing  information is c yc led  throug h sixteen (0-15) frames (eac h c ontaining 
c hannels 0-31).
Within the 16-frame c yc le, b it 1 of c hannel 0 c yc les throug h three func tions:
nWhen the CRC-4 error c hec king  sc heme is used , a CRC bit is enc od ed  as 
the first p osition of all the even-numb ered  frames. CRC-4 is a 4-b it error 
d etec tion c od e. Eac h 16-frame c yc le c ontains two CRC-4 error c od es. 
hen CRC-4 is not used , the first-b it of even-numb ered  frames is 
unassig ned.
nThe first b it of frames 1, 3, 5, 7, 9, and  11 c ontains a framing -p attern bit. In 
the 16-frame c yc le, the framing  p attern is “ 001011.”
nThe first b it of frames 13 and  15 c ontain remote-end  error b its. In the 
rec eive d irec tion, a 0 ind ic ates an error. In the transmit d irec tion, the 
d etec tion of an error is ind ic ated  b y c hang ing  the 1 to a 0.
Note that the TN464C d oes not c hec k the rec eived  remote end  error b its 
and  always transmits ones in the remote end  error b its. The Tn464D and  
later circuit packs will perform remote end error reporting.
In ad d ition, b its 2 throug h 8 of even-numb ered  frames c ontain the following  
framing  p attern: 0011011. In od d -numb ered  frames: 
nBit 2 is always 1.
nBit 3 c ontains a remote frame alarm b it. When this b it is eq ual to 1, the 
alarm is set.
nBits 4 throug h 8 are unassig ned .