
Figure 33. Two LIU’s, Each Monitoring the Transmit Output Signal of the Other LIU IC .............................. 43
4.6 T
HE
TAOS (T
RANSMIT
A
LL
O
NE
S) F
EATURE
....................................................................................... 43
C
OMMAND
R
EGISTER
CR1 (A
DDRESS
= 0
X
01) ........................................................................................... 43
5.0 The Microprocessor Serial Interface ........................................................................ 44
5.1 D
ESCRIPTION
OF
THE
C
OMMAND
R
EGISTERS
........................................................................................ 44
T
ABLE
5: A
DDRESSES
AND
B
IT
F
ORMATS
OF
XRT73LC00A C
OMMAND
R
EGISTERS
........................................... 44
D
ESCRIPTION
OF
B
IT
-F
IELDS
FOR
E
ACH
C
OMMAND
REGISTER
..................................................................... 44
5.1.1 Command Register - CR0 ...................................................................................................... 44
5.1.2 Command Register - CR1 ...................................................................................................... 45
5.1.3 Command Register - CR2 ...................................................................................................... 46
5.1.4 Command Register - CR3 ...................................................................................................... 46
5.1.5 Command Register - CR4 ...................................................................................................... 46
5.2 O
PERATING
THE
M
ICROPROCESSOR
S
ERIAL
I
NTERFACE
. ...................................................................... 47
T
ABLE
6: L
OOP
-B
ACK
M
ODES
........................................................................................................................... 47
Figure 34. Microprocessor Serial Interface Data Structure ............................................................................ 48
O
RDERING
I
NFORMATION
............................................................................................................................ 49
PACKAGE DIMENSIONS ................................................................................................. 49
R
EVISION
H
ISTORY
..................................................................................................................................... 50
XRT73LC00A
E3/DS3/STS-1 LINE INTERFACE UNIT
PRELIMINARY
REV. P1.0.0
III
Figure 28. The Behavior of the RPOS and RCLK1 Output Signals While the XRT73LC00A is Transmitting Sin-
gle-Rail Data to the Receiving Terminal Equipment ..................................................................... 38
4.0 Diagnostic Features of the XRT73LC00A ................................................................ 38
4.1 T
HE
A
NALOG
L
OCAL
L
OOP
-B
ACK
M
ODE
.............................................................................................. 38
Figure 29. The Analog Local Loop-Back in the XRT73LC00A ....................................................................... 39
C
OMMAND
R
EGISTER
CR4 (A
DDRESS
= 0
X
04) ........................................................................................... 39
4.2 T
HE
D
IGITAL
L
OCAL
L
OOP
-B
ACK
M
ODE
............................................................................................... 39
Figure 30. The Digital Local Loop-Back path in the XRT73LC00A ................................................................ 40
C
OMMAND
R
EGISTER
CR4 (A
DDRESS
= 0
X
04) ........................................................................................... 40
4.3 T
HE
R
EMOTE
L
OOP
-B
ACK
M
ODE
......................................................................................................... 40
Figure 31. The Remote Loop-Back Path in the XRT73LC00A ....................................................................... 41
4.4 TXOFF F
EATURES
.............................................................................................................................. 41
C
OMMAND
R
EGISTER
CR4 (A
DDRESS
= 0
X
04) ........................................................................................... 41
4.5 T
HE
T
RANSMIT
D
RIVE
M
ONITOR
F
EATURES
.......................................................................................... 41
C
OMMAND
R
EGISTER
CR1 (A
DDRESS
= 0
X
01) ........................................................................................... 41
Figure 32. The XRT73LC00A Employing the Transmit Drive Monitor Features ............................................. 42