User Manual

Central Terminal Level Control Unit
Operators Manual
GSI 002
605-0000-428
Issue 1.2. Date 5/11/98
Page 4 of 14
4. Level Control Unit
4.1. Mechanical
The Level Control Unit is fitted at the base of the Central Terminal Rack and
measures 600mm wide, 300mm deep. 100mm high.
1
Dip/
LNA
TX
Filter
DC In
1 1
1
1
237
Shelf 4 Shelf 1
Shelf 3 Shelf 2
Terminal
OKFRU Fail
Front
Left Side Right Side
AB
4.2. RF Interconnect
The Level Control Unit has two RF ports (SMA connectors 50 Ohm
impedance) and is connected to the RF antenna port using one length of RF
cable and one coupler per antenna port. Unused ports are terminated using 50
ohm RF loads. All couplers and cables are marked to show insertion loss.
4.3. Shelf Controller Communications
On CT racks cables with 25pin D type adapters allow communication from the
management system port of each modem shelf to the Level Control Unit. A
female 25 pin D type connection is presented on the adapter for connection to
the Sitespan Management system.
4.4. DC Connections
The DC Supply is connected to a 15 way D-type connector on the right side of
the unit. The Battery return is connected to pin 4 and duplicated supplies to
Batt-ve(0) to pin 8 and Batt-ve(1) to pin 7 .
4.5. Handheld Terminal
A handheld terminal is used as the man-machine interface for the Level
Control Unit. This interface is menu driven and the number of data entries are
kept to the absolute minimum to reduce the software complexity.