XRT73L03 Datasheet, PDF (48/62 Pages) Exar Corporation – 3 CHANNEL E3/DS3/STS-1 LINE INTERFCE UNIT

XRT73L03 3 CHANNEL E3/DS3/STS-1 LINE INTERFACE UNIT
REV. P1.0.13
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PRELIMINARY
FIGURE 28. THE BEHAVIOR OF THE RPOS AND RXCLK OUTPUT SIGNALS WHILE THE XRT73L03 IS TRANSMIT-
TING SINGLE-RAIL DATA TO THE RECEIVING TERMINAL EQUIPMENT
RPOS
RxClk
NOTE: The RNEG(n) output pin is internally tied to Ground
whenever this feature is implemented.
3.7 SHUTTING OFF THE RECEIVE SECTION
The Receiver Section in each channel of the
XRT73L03 can be shut off. This feature may be use-
ful in some redundant system designs. Particularly, in
those designs where the Receive Termination in the
Secondary LIU Line Card has been switched-out and
is not receiving any traffic in parallel with the Primary
Line Card. In this case, it is a waste of power if the
LIU on the Secondary Line Card is consuming the
normal amount of current. This feature can permit
powering down the Receive Section of the LIU’s on
the Secondary Line Card which reduces their power
consumption by approximately 80%.
a. Operating in the Hardware Mode
Shut off the Receive Section of Channel(n) by pulling
the RxOFF(n) input pin (pin 15, 19 or 70 respectively)
“High". Turn on the Receive Section of Channel(n) by
pulling the RxOFF(n) input pin to "Low".
b. Operating in the HOST Mode
Shut off the Receive Section of Channel(n) by writing
a "1" into the RxOFF(n) bit-field in Command Regis-
ter CR3-(n). Turn on the Receive Section of Chan-
nel(n) by writing a "0" into the RxOFF(n) bit-field in
Command Register CR3-(n).
D4
SR/(DR)_(n)
X
COMMAND REGISTER CR3-(N)
D3
D2
D1
LOSMUT(n)
RxOFF(n)
RxClk(n)INV
X
1
X
D0
Reserved
X
45