User Manual

AS4000 Wireless Local Loop
System Overview
GSI 003
605-0000-430
Issue 1.2 Date 7/4/99
Page 4 of 6
The specific impedance of the NTU allows tests to be performed by the CRU to ascertain
whether the NTU is present on a line and if there is any CPE attached.
1.5 Network Termination Unit when using ST-D128
The Single Network Termination Unit can be cabled either from the junction box or cabled
direct from the CRU. The 2 Mbit/s Tx and Rx pairs are cabled using twisted pairs. The
D128 provides 2 x 64 kbit/s circuits embedded as time slots 1&2 respectively in a 2 Mbit/s
G703 interface to the CPE. The Presentation is RJ45 @ 120Ω.
1.6 D128 Interface Converter
The interface converter allows customers whose equipment does not support the E1
presentation to be presented with either 2 x 64 kbit/s X.21 interfaces or 2 x V.35 interfaces.
1.7 Network Termination Unit when using ST-I1
The Subscriber interface is an “S” Basic Rate Interface (2B+D) at the customer premises,
and terminates on an RJ45 connector.
1.8 AC Power Supply Unit (Type 1)
The ST equipment is powered from the AC mains supply available at the customer’s
premises. The Power supply consists of an AC/DC converter, that converts the customers
230/110V (1 Amp) AC mains supply to a 24 Volt DC supply, for the ST-V2/ST-I1 and 30
Volt DC for the D128. It also uses a Junction Box that facilitates the connection of the DC
supply to the Drop Cable. The Junction Box also contains test access and connection points
to connect NTU’s to the Drop Cable.