363-206-285
Circuit Pack Descriptions
7-24 Issue 3 June 2001
Figure 7-8. TG Option Switches for DDM-2000 OC-3 (Sheet 2 of 2)
TG Quick Reference Summary 7
Provisioned Modes 7
The TG circuit pack can be provisioned through on-board option switches to any
one of three timing modes: (a) External timing mode (b) Line (formerly loop) timing
mode or (c) Free-running mode.
In addition, the TGS circuit pack can be provisioned through on-board option
switches to provide a DS1 output for network timing distribution or for shelf timing
distribution. Line (formerly loop) timing from the main OC-3 line is the factory
default. Line (formerly loop) timing for function unit C can be provisioned with the
CIT.
Holdover Mode 7
The holdover mode maintains the last good reference frequency during
unprotected failure of external or line (formerly loop)-timing references.
Maintenance and Control 7
The following maintenance functions are provided on the TG circuit pack: (a) DS1
reference monitoring, (b) TG and OLIU circuit pack protection switching, and (c)
inventory information (
CLEI
code, date of manufacture, etc
.).
Equalizer Switch Settings
Equalization (Note) S2-1 S2-2 S2-3
0' to 131' ON ON OFF
131' to 262' ON OFF ON
262' to 393' ON OFF OFF
393' to 524' OFF ON ON
524' to 655' OFF ON OFF
Invalid OFF OFF OFF
Invalid OFF OFF ON
Invalid ON ON ON
Note: Distance in feet for 22 gauge PIC (ABAM) cable.