User Manual

AS4000 Wireless Local Loop
System Overview
GSI 003
605-0000-430
Issue 1.2 Date 7/4/99
Page 2 of 6
1.1 Customer Radio Unit
The 2.0 - 2.3GHz Band and 2.3 - 2.5GHz Band CRUs contain two flat-plate integrated
antennas and the 2.0 - 2.3GHz Band CRU contains a single flat-plate integrated antenna.
They contain most of the electronics circuitry necessary to fulfil the function of terminating
the RF communications link to the CT equipment. In addition to carrying traffic, this link
carries signalling and management (control) information.
The CRU is a sealed weatherproof unit to tested to IP55 which is mounted on the outside
of the customer’s premises. The unit is normally positioned on an outside wall or a
mounting that faces the general direction of the CT antenna. The ST should be sited to
avoid large obstructions in proximity to and in line of sight from the ST to the Antenna .
See the ST installation and commissioning manual for deployment rules.
1.2 CRU Mounting Bracket
The CRU Mounting Bracket provides adjustment (in the azimuth plane) of the CRU in an
arc over 150°, the optimum positioning being determined by measuring the strength of the
incoming signal, usually in the direction of the CT antenna.
1.3 Drop Cable
The drop cable connects the PSU/NTUs to the CRU via an environmentally protected
connector that is plugged into the backplate of the CRU. It consists of 8 electrical
connections:
• 2 wires for DC power for the CRU
• 2 wires for alarm communications between the units
• 2 x 2 wire VF connectors ST-V2 (see Figure 20)
or 2 Mbit/s Tx & Rx connectors ST-D128
or 1 ISDN 2B+D connection STx & SRx .