
DS26518 8-Port T1/E1/J1 Transceiver 
2 of 286 
TABLE OF CONTENTS 
1.
DETAILED DESCRIPTION.................................................................................................9
2.
FEATURE HIGHLIGHTS..................................................................................................10
G
ENERAL
......................................................................................................................................10
L
INE 
I
NTERFACE
............................................................................................................................10
C
LOCK 
S
YNTHESIZERS
..................................................................................................................10
J
ITTER 
A
TTENUATOR
.....................................................................................................................10
F
RAMER
/F
ORMATTER
....................................................................................................................11
S
YSTEM 
I
NTERFACE
 ......................................................................................................................11
HDCL C
ONTROLLERS
 ...................................................................................................................12
T
EST AND 
D
IAGNOSTICS
................................................................................................................12
M
ICROCONTROLLER 
P
ARALLEL 
P
ORT
.............................................................................................12
2.10
S
LAVE 
S
ERIAL 
P
ERIPHERAL 
I
NTERFACE 
(SPI) F
EATURES
............................................................12
3.
APPLICATIONS ...............................................................................................................13
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
4.
SPECIFICATIONS COMPLIANCE...................................................................................14
5.
ACRONYMS AND GLOSSARY .......................................................................................16
6.
MAJOR OPERATING MODES.........................................................................................17
7.
BLOCK DIAGRAMS.........................................................................................................18
8.
PIN DESCRIPTIONS........................................................................................................20
P
IN 
F
UNCTIONAL 
D
ESCRIPTION
......................................................................................................20
FUNCTIONAL DESCRIPTION .........................................................................................28
P
ROCESSOR 
I
NTERFACE
................................................................................................................28
9.1.1
SPI Serial Port Mode............................................................................................................................ 28
9.1.2
SPI Functional Timing Diagrams ......................................................................................................... 28
9.2
C
LOCK 
S
TRUCTURE
.......................................................................................................................31
9.2.1
Backplane Clock Generation ............................................................................................................... 31
9.2.2
CLKO Output Clock Generation........................................................................................................... 32
9.3
R
ESETS AND 
P
OWER
-D
OWN 
M
ODES
..............................................................................................33
9.4
I
NITIALIZATION AND 
C
ONFIGURATION
..............................................................................................34
9.4.1
Example Device Initialization and Sequence....................................................................................... 34
9.5
G
LOBAL 
R
ESOURCES
 ....................................................................................................................34
9.6
P
ER
-P
ORT 
R
ESOURCES
 ................................................................................................................34
9.7
D
EVICE 
I
NTERRUPTS
 .....................................................................................................................34
9.8
S
YSTEM 
B
ACKPLANE 
I
NTERFACE
 ...................................................................................................36
9.8.1
Elastic Stores....................................................................................................................................... 36
9.8.2
IBO Multiplexing................................................................................................................................... 39
9.8.3
H.100 (CT Bus) Compatibility .............................................................................................................. 45
9.8.4
Transmit and Receive Channel Blocking Registers............................................................................. 47
9.8.5
Transmit Fractional Support (Gapped Clock Mode)............................................................................ 47
9.8.6
Receive Fractional Support (Gapped Clock Mode)............................................................................. 47
9.9
F
RAMERS
......................................................................................................................................48
9.9.1
T1 Framing........................................................................................................................................... 48
9.9.2
E1 Framing........................................................................................................................................... 51
9.9.3
T1 Transmit Synchronizer.................................................................................................................... 53
9.9.4
Signaling .............................................................................................................................................. 54
9.9.5
T1 Data Link......................................................................................................................................... 59
9.9.6
E1 Data Link......................................................................................................................................... 61
9.9.7
Maintenance and Alarms ..................................................................................................................... 62
8.1
9.
9.1