XRT79L72 Datasheet, PDF (44/72 Pages) Exar Corporation – 2 - CHANNEL DS3/E3 ATM UNI/PPP COMBO IC

XRT79L72
REV. P1.0.2
PIN #
AE2
Y23
NAME
TAISEN_0
TAISEN_1
AE11
AE15
MTIP_0
MTIP_1
AD11
AD15
MRING_0
MRING_1
PRELIMINARY
xr
2 - CHANNEL DS3/E3 ATM UNI/PPP COMBO IC
TYPE
DESCRIPTION
I Transmit Alarm Indication Signal Enable Input
I This input pin permits the user to command the Transmit DS3/E3 Framer block to
transmit an AIS pattern to the remote terminal equipment.
Setting this input pin "high" configures the Transmit DS3/E3 Framer block to trans-
mit AIS pattern to the remote terminal equipment. Setting this input pin "low" con-
figures the Transmit DS3/E3 Framer block to NOT transmit an AIS pattern to the
remote terminal equipment.
NOTE: For normal operation, or if the user wishes to control the "Transmit AIS"
function via Software Control, the user should tie this input pin to GND.
I Transmit Drive Monitor Input pin - Positive Polarity Input:
I These input pins along with MRING function as the Transmit Drive Monitor Output
(DMO) input monitoring pins.
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
(DMO) input monitoring pins.
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
RTIP_0
I
AD16
RTIP_1
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 XRT79L72.
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.
41