XRT73LC04A_08 Datasheet, PDF (9/64 Pages) Exar Corporation – 4 CHANNEL DS3/E3/STS-1 LINE INTERFACE UNIT

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REV. 1.0.2
TRANSMIT INTERFACE
PIN #
44
43
137
138
NAME
TxLEV_0
TxLEV_1
TxLEV_2
TxLEV_3
131
TxOFF
XRT73LC04A
4 CHANNEL DS3/E3/STS-1 LINE INTERFACE UNIT
TYPE
I
I
DESCRIPTION
Transmit Line Build-Out Enable/Disable Select - Channel (n):
This input pin permits the Transmit Line Build-Out circuit, within Channel
(n), to be enabled or disabled. In E3 mode, this pin has no effect on the
transmit pulse shape.
Setting this pin to "High" disables the Line Build-Out circuit. In this
mode, Channel (n) outputs partially-shaped pulses onto the line via the
TTIP_(n) and TRing_(n) output pins.
Setting this pin to "Low" enables the Line Build-Out circuit within Channel
(n). In this mode, Channel (n) outputs shaped pulses onto the line via
the TTIP_(n) and TRing_(n) output pins.
To comply with the Isolated DSX-3/STSX-1 Pulse Template Require-
ments per Bellcore GR-499-CORE or Bellcore GR-253-CORE:
1. Set this input pin to "1" if the cable length between the Cross-Connect
and the transmit output of Channel (n) is greater than 225 feet.
2. Set this input pin to "0" if the cable length between the Cross-Connect
and the transmit output of Channel (n) is less than 225 feet.
This pin is active only if the following two conditions are true:
a. The XRT73LC04A is configured to operate in either the DS3 or
SONET STS-1 Modes.
b. The XRT73LC04A is configured to operate in the Hardware Mode.
NOTE: This pin to should be tied to GND if the XRT73LC04A is going to
be operating in the HOST Mode, (internally pulled-down).
Transmitter OFF Input:
Setting this input pin "High" turns off all of the Transmitter Sections. In
this mode the TTIP and TRing outputs are tri-stated.
NOTES:
1. This input pin controls the TTIP and TRing outputs even when
the XRT73LC04A is operating in the HOST Mode.
2. For HOST Mode Operation, this pin is tied to GND if the Trans-
mitter is intended to be turned off via the Microprocessor Serial
Interface.
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