
DS26524 Quad T1/E1/J1 Transceiver 
2 of 273 
TABLE OF CONTENTS 
1.
DETAILED DESCRIPTION.................................................................................................9
M
AJOR 
O
PERATING 
M
ODES
.............................................................................................................9
FEATURE HIGHLIGHTS..................................................................................................10
G
ENERAL
......................................................................................................................................10
L
INE 
I
NTERFACE
............................................................................................................................10
C
LOCK 
S
YNTHESIZER
....................................................................................................................10
J
ITTER 
A
TTENUATOR
.....................................................................................................................10
F
RAMER
/F
ORMATTER
....................................................................................................................10
S
YSTEM 
I
NTERFACE
 ......................................................................................................................11
HDLC C
ONTROLLERS
 ...................................................................................................................12
T
EST AND 
D
IAGNOSTICS
................................................................................................................12
M
ICROCONTROLLER 
P
ARALLEL 
P
ORT
.............................................................................................12
APPLICATIONS ...............................................................................................................13
1.1
2.
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
3.
4.
SPECIFICATIONS COMPLIANCE...................................................................................14
5.
ACRONYMS AND GLOSSARY .......................................................................................16
6.
BLOCK DIAGRAMS.........................................................................................................17
7.
PIN DESCRIPTIONS........................................................................................................19
P
IN 
F
UNCTIONAL 
D
ESCRIPTION
......................................................................................................19
FUNCTIONAL DESCRIPTION .........................................................................................26
M
ICROPROCESSOR 
I
NTERFACE
......................................................................................................26
8.1.1
Parallel Port Mode................................................................................................................................ 26
8.2
C
LOCK 
S
TRUCTURE
.......................................................................................................................26
8.2.1
Backplane Clock Generation ............................................................................................................... 26
8.3
R
ESETS AND 
P
OWER
-D
OWN 
M
ODES
..............................................................................................28
8.4
I
NITIALIZATION AND 
C
ONFIGURATION
..............................................................................................29
8.4.1
Example Device Initialization Sequence.............................................................................................. 29
8.5
G
LOBAL 
R
ESOURCES
 ....................................................................................................................29
8.6
P
ER
-P
ORT 
R
ESOURCES
 ................................................................................................................29
8.7
D
EVICE 
I
NTERRUPTS
 .....................................................................................................................29
8.8
S
YSTEM 
B
ACKPLANE 
I
NTERFACE
 ...................................................................................................31
8.8.1
Elastic Stores....................................................................................................................................... 31
8.8.2
IBO Multiplexer..................................................................................................................................... 34
8.8.3
H.100 (CT Bus) Compatibility .............................................................................................................. 40
8.8.4
Receive and Transmit Channel Blocking Registers............................................................................. 41
8.8.5
Transmit Fractional Support (Gapped Clock Mode)............................................................................ 41
8.8.6
Receive Fractional Support (Gapped Clock Mode)............................................................................. 41
8.9
F
RAMERS
......................................................................................................................................42
8.9.1
T1 Framing........................................................................................................................................... 42
8.9.2
E1 Framing........................................................................................................................................... 45
8.9.3
T1 Transmit Synchronizer.................................................................................................................... 47
8.9.4
Signaling .............................................................................................................................................. 48
8.9.5
T1 Data Link......................................................................................................................................... 52
8.9.6
E1 Data Link......................................................................................................................................... 54
8.9.7
Maintenance and Alarms ..................................................................................................................... 55
8.9.8
E1 Automatic Alarm Generation .......................................................................................................... 58
8.9.9
Error-Count Registers.......................................................................................................................... 59
8.9.10
DS0 Monitoring Function...................................................................................................................... 61
7.1
8.
8.1