
XRT72L50
SINGLE CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER
REV. P1.1.3
á
PRELIMINARY
15
76
RLOL
I
Receive Loss of Lock Indicator - from the XRT7300 DS3/E3 Line Inter-
face Unit IC:
This input pin is intended to be connected to the RLOL (Receive Loss of Lock)
output pin of the XRT7300 Line Interface Unit IC. The user can monitor the
state of this pin by reading the state of Bit 1 (RLOL) within the Line Interface
Scan Register (Address = 0x81).
If this input pin is "low", then it means that the "clock recovery phase-locked-
loop" circuitry, within the XRT7300 device is properly locked onto the incom-
ing DS3 E3 data-stream; and is properly recovering clock and data from this
DS3/E3 data-stream. However, if this input pin is "high", then it means that the
phase-locked-loop circuitry, within the XRT7300 device has lost lock with the
incoming DS3 or E3 data-stream, and is not properly recovering clock and
data.
For more information on the operation of the XRT7300 DS3/E3 Line Interface
Unit IC, please consult the "XRT7300 DS3/E3 Line Interface Unit" data sheet.
If the customer is not using the XRT7300 DS3/E3 Line Interface Unit IC, he/
she can use this input pin for other purposes.
77
ExtLOS
I
Receive LOS (Loss of Signal) Indicator Input (from XRT7300 LIU IC):
This input pin is intended to be connected to the RLOS (Receive Loss of Sig-
nal) output pin of the XRT7300 Line Interface Unit IC. The user can monitor
the state of this pin by reading the state of Bit 0 (RLOS) within the Line Inter-
face Scan Register (Address = 0x81).
If this input pin is "low", then it means that the XRT7300 device is currently
NOT declaring an "LOS (Loss of Signal) condition. However, if this input pin is
"high", then it means that the XRT7300 device is currently declaring an LOS
(Loss of Signal) condition.
For more information on the operation of the XR-T7300 DS3/E3 Line Receiver
IC, please consult the "XRT7300 DS3/STS-1/E3 Line Interface Unit IC" data
sheet.
Asserting the RLOS input pin will cause the XRT72L50 DS3/E3 Framer
device to declare an "LOS (Loss of Signal) condition. Therefore, this input pin
should not be used as a general purpose input.
78
DMO
I
"Drive Monitor Output" Input (from the XR-T7300 DS3/E3 Line Interface
Unit IC):
This input pin is intended to be tied to the DMO output pin of the XRT7300
DS3/E3 Line Interface Unit IC. The user can determine the state of this input
pin by reading Bit 2 (DMO) within the Line Interface Scan Register (Address =
0x81). If this input signal is "high", then it means that the drive monitor cir-
cuitry (within the XRT7300 DS3/E3 Line Interface Unit IC) has not detected
any bipolar signals at the MTIP and MRING inputs within the last 128 (32 bit-
periods. If this input signal is "low", then it means that bipolar signals are
being detected at the MTIP and MRING input pins of the XRT7300 device.
If this customer is not using the XR-T7300 DS3/E3 Line Interface Unit IC, then
he/she can use this input pin for a variety of other purposes.
79
VDD
****
Power Supply 3.3V + 5%
80
GND
****
Ground
PIN DESCRIPTION
P
IN
#
P
IN
N
AME
T
YPE
D
ESCRIPTION