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
Physical Layer 
Page 4-27 The Digital Loss Plan 
4
The d ig ital loss plan is sig nific antly d ifferent from the VNL. Sinc e the two loss 
p lans d o d iffer, it c annot b e assumed  that the p ort-to-p ort losses measured in an 
all-d ig ital network or in a c omb ined  d ig ital and  analog  network are the same as 
the loss measured  b etween the same p orts in an all-analog...

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 4-28 The Digital Loss Plan 
4
p ac k typ e (DS1 or analog ). Before the availab ility of this ad ministration c ap ab ility, 
loss-p ad -g roup  assig nment had  b een fixed , transp arent, and  d ic tated  b y the 
trunk typ e and  p ort c irc uit p ac k typ e b eing  used . For examp le with fixed loss, a 
p ort on a G2.2 c irc uit pac k ad ministered  as trunk...

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 4-29 The Digital Loss Plan 
4
Althoug h the d ig ital loss p lan p rovid es for the assig nment of a loss-p ad  g roup  
ind ep end ent of p ort typ e (analog  or d ig ital), there are c ertain restric tions. 
Ad ministration d oes not p rovid e for alternate p ort ap p earanc e on DS1 p ort c irc uit 
p ac ks for the following  lab eled  p ad  g roup s: analog...

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 4-30 The Digital Loss Plan 
4
Port-to-Port Loss Values
The p ort-to-p ort loss values shown in Tab le 4-10, can be used to determine the 
c orrec t loss b etween two p rop erly terminated  p orts of a d ig ital switc h.
To d etermine the c orrec t end-to-end  loss for a tand em c onnec tion (throug h b oth 
an analog  and dig ital switc h), simp ly add  up  the...

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 4-31 The Digital Loss Plan 
4
NOTE:
A terminal b alanc ed  trunk is d efined  as meeting  an ERL of g reater than or 
eq ual to 18 dB and  an SRL of g reater than or eq ual to 10 dB, when 
measured  into a q uiet termination at the CO.
nPort-to-p ort losses in Generic  2.2 and  Generic  3V2 c onform to the ANSI 
digital loss plan standard. Tab le 4-10
 is an exc...

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 4-32 The Digital Loss Plan 
4
Terminating a DS1 at a Channel Bank
The DS1 c hannels that leave the switc h in d ig ital form and  are c onverted  to 
analog  form b y a c hannel b ank are c alled  \E2
c omb ination c hannels. Three b asic  
types are described below.
Tie Trunk Ports
To ob tain the req uired  c hannel unit losses for c omb ination tie trunks,...

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 4-33 Synchronization 
4
Synchronization
The DS1/CEPT1 transmit and  rec eive buffers for DEFINITY systems operate from 
a sing le external or internal c lock. Each d ig ital switc h c an accommod ate multiple 
DS1/CEPT1 or T1/E1 sp ans that link multip le switc hes. These may inc lud e b oth 
ISDN-PRI and  DS1/CEPT1 links. Sinc e eac h switc h c an transmit at a...

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 4-34 Synchronization 
4
a p air of analog  switc hing  systems c onnec ted b y T1-c arrier fac ilities. For this 
arrang ement, the transmitting  portion of eac h c hannel b ank ind ep end ently 
d etermines the c loc k rates. The rec eiving  p ortion of eac h c hannel b ank d erives 
its c loc k from the inc oming  d ig ital b it stream. In this arrangement, the...

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 4-35 Synchronization 
4
the average transmit bit-clock rate, the receive buffer will eventually underrun. It 
is nec essary to p revent overruns (d eletions) and  und erruns (repetitions) b y 
sync hronizing  the network p roperly. Imp rop er sync hronization results in b uffers 
rep eating  or d eleting b its in 1-frame inc rements.
NOTE:
The d eletion or rep...

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 4-36 Synchronization 
4
Synchronization Hierarchy
Within North Americ a, all p rivate d igital telec ommunic ations fac ilities that 
c onnec t to the p ub lic  dig ital network must ob tain sync hronization b y the 
hierarc hic al method. This method  is based  on:
1. Controlling the slip  rate to provid e satisfac tory servic e to the c ustomer
2. Maximum...