Circuit Pack Descriptions
Issue 8.0 July 2002
7-123
Reference Input Functions 7
The incoming DS1 timing references are monitored for:
a. Loss of signal (175 ±75 consecutive zeros)
b. DS1 alarm indication signal (AIS) for at least 125 µsec
c. Bit error rate (BER) greater than 2x10
-4
for a period ≥ 3 seconds
d. Loss of frame for a period ≥ 3 seconds
e. Excessive out-of-frame count
f. Clock frequency out of specifications.
If the microprocessor on one TG3 (DS1) circuit pack detects an incoming DS1
reference failure, it will signal the LNCTL circuit pack. The LNCTL circuit pack will
signal the microprocessor on the companion TG3 (DS1) circuit pack to accept the
secondary DS1 reference signal.
Clock Output Functions 7
The TG3 (DS1) circuit pack provides the following output signals:
a. A 155.52 MHz signal is distributed to the OC48 Transmitter (OC48
TRMTR) and low speed interface circuit packs.
b. A 25.92 MHz cross-coupled reference signal is distributed to the
companion TG3 (DS1) circuit pack.
c. A 1.544 MHz (DS1) signal is made available as a synchronization
reference for the office BITS clock or other central office equipment.
Control Functions 7
The TG3 (DS1) circuit pack provides the following control functions:
a. Selects the primary or secondary timing reference signal in the loop timed
and phase locked modes
b. Performs internal fault detection and interfaces with the LNCTL circuit pack
using the BCLAN
c. Controls the circuit pack faceplate FAULT LED
d. Stores inventory information (CLEI code, serial number, etc.).
Maintenance Functions 7
The TG3 (DS1) circuit pack provides the following maintenance functions:
a. Monitors the DS1 timing references
b. Monitors the internal clock hardware
c. Detects and inserts DS1 alarm indication signals (AIS).
To Next Page
Loading...
Need help?
General