XRT79L74 Datasheet, PDF (44/70 Pages) Exar Corporation – 4 - CHANNEL DS3/E3 ATM UNI/PPP COMBO IC

XRT79L74
REV. P1.0.0
PIN #
AE11
AE15
AE7
AE19
NAME
MTIP1
MTIP2
MTIP3
MTIP4
AD11
AD15
AD7
AD19
MRING1
MRING2
MRING3
MRING4
PRELIMINARY
4 - CHANNEL DS3/E3 ATM UNI/PPP COMBO IC
TYPE
DESCRIPTION
I Transmit Drive Monitor Input pin - Positive Polarity Input:
I These input pins along with MRING function as the Transmit Drive Monitor Output
I ^{(DMO) input monitoring pins.}
I ^{If the user wishes to (1) monitor the Transmit Output line signal and (2) to perform}
this monitoring externally, then the user MUST connect these particular pins to the
TTIPn output pin via a 274Ω series resistor. Similarly, the user MUST also con-
nect the MRINGn input pin to the TRINGn output pin via a 274Ω series resistor.
The MTIPn and MRINGn input pins will continuously monitor the Transmit Output
line signal via the TTIPn and TRINGn output pins for bipolar activity. If these pins
do not detect any bipolar activity for 128 bit periods, then the Transmit Drive Moni-
tor circuit will drive the DMOn output pin "High" in order to denote a possible fault
condition in the Transmit Output Line signal path.
NOTE: These input pins are inactive if the user choose to internally monitor the
Transmit Output line signal.
I Transmit Drive Monitor Input pin - Positive Polarity Input:
I These input pins along with MTIP function as the Transmit Drive Monitor Output
I ^{(DMO) input monitoring pins.}
I ^{If the user wishes to (1) monitor the Transmit Output line signal and (2) to perform}
this monitoring externally, then the user MUST connect these particular pins to the
TRINGn output pin via a 274Ω series resistor. Similarly, the user MUST also con-
nect the MTIPn input pin to the TTIPn output pin via a 274Ω series resistor.
The MTIPn and MRINGn input pins will continuously monitor the Transmit Output
line signal via the TTIPn and TRINGn output pins for bipolar activity. If these pins
do not detect any bipolar activity for 128 bit periods, then the Transmit Drive Moni-
tor circuit will drive the DMOn output pin "High" in order to denote a possible fault
condition in the Transmit Output Line signal path.
3. These input pins are inactive if the user choose to internally monitor the
Transmit Output line signal.
PIN #
NAME
TYPE
RECEIVE LINE SIDE SIGNALS
AD12
RTIP1
I
AD16
RTIP2
I
AD8
RTIP3
I
AD20
RTIP4
I
DESCRIPTION
Receive Input - Positive Polarity Signal:
These input pins, along with the RRINGn input pins, function as the Receive
DS3/E3 Line input signal receiver of the XRT79L74.
The user is expected to connect these signals and the RRINGn input signals to a
1:1 transformer.
Whenever the RTIP/RRING input pins are receiving a positive-polarity pulse
within the incoming DS3 or E3 line signal, these input pins will be pulsed to a
"higher-voltage" than the RRING input pins.
Conversely, whenever the RTIP/RRING input pins are receiving a negative-
polarity pulse within the incoming DS3 or E3 line signal, these input pins will be
pulsed to a "lower-voltage" than the RRING input pins.
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