XRT75L00D Datasheet, PDF (10/92 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
TRANSMIT INTERFACE
PIN #
SIGNAL NAME
TYPE
DESCRIPTION
51
TRING
O Transmit Ring Output
The XRT75L00D uses this pin along with TTIP to transmit a bipolar signal to the
line using a 1:1 transformer.
1
TxLEV
I
Transmit Line Build-Out Enable/Disable Select
This input pin is used to enable or disable the Transmit Line Build-Out circuit.
Setting this pin to "High" disables the Line Build-Out circuit. In this mode, par-
tially-shaped pulses are output onto the line via the TTIP and TRING output
pins.
Setting this pin to "Low" enables the Line Build-Out circuit. In this mode, shaped
pulses are output onto the line via the TTIPand TRING output pins.
To comply with the Isolated DSX-3/STSX-1 Pulse Template Requirements per
Bellcore GR-499-CORE or Bellcore GR-253-CORE:
1. Set this pin to "1" if the cable length between the Cross-Connect and the
transmit output is greater than 225 feet.
2. Set this pin to "0" if the cable length between the Cross-Connect and the
transmit output is less than 225 feet.
This pin is active only if the following two conditions are true:
a. The XRT75L00D is configured to operate in either the DS3 or SONET STS-1
Modes.
b. The XRT75L00D is configured to operate in the Hardware Mode.
NOTES:
1. This pin is internally pulled down.
2. If the XRT75L00D is configured in HOST mode, this pin may be tied to
GND.
5