XRT72L56 Datasheet, PDF (149/486 Pages) Exar Corporation – SIX CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER

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SIX CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER
PRELIMINARY
XRT72L56
REV. P1.1.2
modes, please consult the appropriate LIU IC Data
Sheet.
Currently the following “XRT73L0X Family of DS3/E3/
STS-1 LIU IC Data Sheets are now available:
• XRT7300 1-Channel DS3/E3/STS-1 LIU IC (5V)
• XRT73L00 1-Channel DS3/E3/STS-1 LIU IC (3.3V)
• XRT7302 2-Channel DS3/E3/STS-1 LIU IC (5V)
• XRT73L03 3-Channel DS3/E3/STS-1 LIU IC (3.3V)
• XRT73L04 4-Channel DS3/E3/STS-1 LIU IC (3.3V)
NOTE: If the customer is not using an Exar XRT73L0X
DS3/E3/STS-1 LIU IC, then this bit-field and the the
LLOOP[n] output pin can be used for other purposes.
2.4.8.20 Line Interface Scan Register
LINE INTERFACE SCAN REGISTER (ADDRESS = 0X81)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
DMO
RLOL
RLOS
RO
RO
RO
RO
RO
RO
RO
RO
0
0
0
0
0
0
0
0
Bit 2 - DMO - (Drive Monitor Output)
This Read-Only bit-field indicates the logic state of
the DMO[n] input pin of the Framer device. This input
pin is intended to be connected to the DMO output
pin of an “Exar XRT73L0X-type” of DS3/E3 LIU IC. If
this bit-field contains a logic "1", then the DMO input
pin is "High". An Exar “XRT73L0X-type” of DS3/E3
LIU IC will set this pin "High" if the drive monitor cir-
cuitry (within the LIU device) has not detected any bi-
polar signals at the MTIP and MRING inputs (of the
LIU device) within the last 128 + 32 bit periods.
Conversely, if this bit-field contains a logic "0", then
the DMO input pin is "High". The DS3/E3 LIU IC will
set this pin "Low" if bipolar signals are being detected
at the MTIP and MRING input pins.
As a consequence, the DMO output pin can be
thought of as a “Transmit Driver Failure” indicator.
NOTE: If this customer is not using an Exar XRT73L0X-type
of DS3/E3 LIU IC, then this input pin and bit-field can be
used for a variety of other purposes.
Bit 1 - RLOL - (Receive Loss of Lock)
This Read-Only bit-field indicates the logic state of
the RLOL[n] input pin of the Framer device. This in-
put pin is intended to be connected to the RLOL out-
put pin of an “Exar XRT73L0X-type” of DS3/E3 LIU
IC. If this bit-field contains a logic "1", then the
RLOL[n] input pin is "High". An Exar “XRT73L0X-
type” of DS3/E3 LIU IC will set this pin "High" if the
clock recovery phase-locked-loop circuitry (within the
LIU device) has lost lock with the incoming DS3/E3
data-stream and is not properly recovering clock and
data.
Conversely, if this bit-field contains a logic "0", then
the RLOL input pin is "Low". The DS3/E3 LIU IC will
hold this pin "Low" as long as this clock recovery
phase-locked-loop circuitry (within the LIU device) is
properly locked onto the incoming DS3 or E3 data-
stream, and is properly recovering clock and data
from this data-stream.
For more information on the operation of these Exar
XRT73L0X-type of DS3/E3/STS-1 LIU ICs, please
consult any of the following data sheets.
• XRT7300 1-Channel DS3/E3/STS-1 LIU IC (5V)
• XRT73L00 1-Channel DS3/E3/STS-1 LIU IC (3.3V)
• XRT7302 2-Channel DS3/E3/STS-1 LIU IC (5V)
• XRT73L03 3-Channel DS3/E3/STS-1 LIU IC (3.3V)
• XRT73L04 4-Channel DS3/E3/STS-1 LIU IC (3.3V)
NOTE: If the customer is not using an Exar XRT73L0X-
type of DS3/E3/STS-1 IC, then this bit-field, and the
RLOL[n] input pin can be used for other purposes.
Bit 0 - RLOS - (Receive Loss of Signal)
This Read-Only bit-field indicates the logic state of
the RLOS[n] input pin of the Framer device. This in-
put pin is intended to be connected to the RLOS out-
put pin of the DS3/E3 LIU IC. If this bit-field contains
a logic "1", then the RLOS[n] input pin is "High". The
LIU device will toggle this signal "High" if it (the LIU
IC) is currently declaring an LOS (Loss of Signal)
condition.
Conversely, if this bit-field contains a logic "0", then
the RLOS input pin is "Low". The LIU device will hold
this signal "Low" if it is NOT currently declaring an
LOS (Loss of Signal) condition.
For more information on the LOS Declaration and
Clearance criteria within the “Exar XRT73L0X type of
DS3/E3/STS-1 LIU IC, please consult any of the fol-
lowing data sheets.
• XRT7300 1-Channel DS3/E3/STS-1 LIU IC (5V)
• XRT73L00 1-Channel DS3/E3/STS-1 LIU IC (3.3V)
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