XRT75L00D Datasheet, PDF (12/92 Pages) Exar Corporation – E3/DS3/STS-1 LINE INTERFACE UNIT WITH SONET DESYNCHRONIZER

XRT75L00D
E3/DS3/STS-1 LINE INTERFACE UNIT WITH SONET DESYNCHRONIZER
REV. 1.0.2
RECEIVE INTERFACE
PIN #
SIGNAL NAME
TYPE
DESCRIPTION
37
RNEG/LCV
O Receive Negative Data Output/Line Code Violation Indicator
Function of these pins depends on whether the XRT75L00D is configured
in Single Rail or Dual Rail mode.
If the XRT75L00D is configured in Dual Rail mode, a negative pulse is output
through RNEG.
In Hardware mode: Tie the pin SR/DR (pin 22) “High” to configure the
XRT75L00D in Single Rail mode and tie “Low” to configure in Dual Rail mode.
In HOST mode: XRT75L00D can be configured in Single Rail or Dual Rail by
setting or clearing the bit in the block control register.
Line Code Violation Indicator
If the XRT75L00D is configured in Single Rail mode then:
Whenever the Receiver Section detects a Line Code violation, it pulses this
output pin “High”. This output pin remains “Low” at all other times. It is
advisable to sample this output pin using the RxClk output signal.
11
RRING
I Receive Ring Input
This input pin along with RTIP is used to receive the bipolar line signal from the
Remote DS3/E3/STS-1 Terminal.
12
RTIP
I Receive TIP Input
This input pin along with RRNG is used to receive the bipolar line signal from
the Remote DS3/E3/STS-1 Terminal.
27
RxMON/
SDO
I
Receive Monitoring Mode or Serial Data Output:
In Hardware mode, when this pin is tied “High” XRT75L00D configures into
monitoring channel. In the monitoring mode, the Receiver is capable of monitor-
ing the signals with 20 dB flat loss plus 6 dB cable attenuation. This allows to
monitor very weak signal before declaring LOS.
In HOST Mode, XRT75L00D can be configured to be a monitoring channel by
setting the bits in the receive control register.
NOTE: If the XRT75L00D is configured in HOST mode, this pin functions as
SDO pin (please refer to the pin description for the Microprocessor
Interface).
7