User Manual

AS4000 Wireless Local Loop
System Overview
GSI 002
605-0000-430
Issue 1.2 Date 7/4/99
Page 2 of 8
The standard management interface at the CT equipment is 1 to 4, V.24 (RS232)
terminations which is connected to serial ports on a PC (1 port for each Modem Shelf).
1 The Network Interfaces
V2 and D128 Systems
The standard traffic interface at the CT equipment is 1-4, 2 Mbit/s, 30 Channel Pulse Code
Modulation (PCM), conforming to ITU Recommendation G703. Between one and four
PCM links are required, on the basis of one link per 15 ST installations. The CT supports
PCM timeslot 16 Channel Associated Signalling (CAS). The CAS type signalling protocol
used is CAS multiframe using ABCD bits. DASS2 signalling protocol is also supported
ISDN
The host network interconnects to the AS4000 using a 2Mbit/s G.703 interfaces. The
signalling is a Q.931 message based “Euro-ISDN” protocol, that meets the NET.5 ISDN
approval standards for Primary Rate Interfaces.
2 Antenna and Feeder Sub-system
2.1 General Description
The antenna and feeder sub-system consists of a high-gain omni-directional antenna
assembly or a directional antenna assembly and low-loss coaxial feeder cables that connect
the antennas to the CT equipment rack. To ensure the antenna assembly is above roof
height and has an unobstructed view of the horizon, an antenna mast may be employed.
Two antennas are employed, one for transmitting RF from modem shelves 1 & 2, and for
receiving the radio links for all four modem shelves, the second for transmitting RF from
modem shelves 3 & 4. In a system where only two shelves are employed only one antenna is
needed.
Antenna Type 2.0 - 2.3GHz
Band
2.3 - 2.5GHz
Band
3.4-3.6GHz
Band
Omni 0.5° Downtilt
Yes Yes Yes
Omni 2.5° Downtilt
Yes No No
Directional 60/65° Azimuth
Yes Yes Yes
Omni Antenna System
The omni antenna sub-system consists of 2 Omni-Directional, Stacked Dipole Antenna,
mounted on a beam of approximately 2 metres in length. This mechanical assembly is
equipped with a bracket for attachment to a suitable pole. The bracket is made of galvanised
steel, and is suitable for deployment in harsh environments. Details of the antenna sub-
system and pole mount are illustrated in Figure 14.