User Manual

Demand Assignment
System Overview GSI 004
605-0000-450
Draft Issue 1.3dr Date 8/02/00
Page 2 of 2
10.1. Power Requirements
The rack requires two DC power supplies. The supply can range from -22 Volt to -60
Volt DC. The input current for a fully loaded Access Concentrator Rack is 13 Amps at
22 Volt reducing to 4.7 Amps at 60 Volt (280W).
10.2. AC Equipment Rack Shelves:
Up to two AC shelves can be equipped within the AC Rack. Each AC shelf consists of:
10.2.1. Access Concentrator Connector Panel
Each Access Concentrator Connector Panel provides E1 network interfaces to each
Modem Shelf at the Central Terminal. Redundant E1 links can also be provided to
maintain the backhaul link to the Central Terminal if the main link fails. The Connector
Panel also provides interfaces to the Switch
10.2.2. Access Concentrator Card Shelf
Each Access Concentrator Card Shelf has:
• Power Supply Units (PSUs). Two PSUs are used to supply power to the Access
Concentrator shelf. The DC load is shared between PSUs and in the event of the
failure of a PSU the other PSU maintains power to the shelf.
• Shelf Controller Card (SC), The SC Card provides the management interface
between the Sitespan and the Modem Shelf. It also holds the configuration details in
NVRAM.
• CT Tributary Unit(s) (CTU) providing the interface between the Access
Concentrator equipment and AS4000 Radio System for traffic and signalling
information. The number of CTUs will be dependent on the configuration.
• Switch Tributary Unit(s) (XTU). These cards provide the interface between the
Access Concentrator equipment and the Switch. The number and type of XTUs will
be dependent on the configuration. XTUs are availiable for CAS, Data, Isdn, V5.1
and V5.2
• Compression Card(s). (CU) The purpose of the DA Compression Card is to
provide ADPCM transcoding on a per channel / timeslot basis in both the CT DA
Rack and Access Concentrator. It is initialised by the Shelf Controller but controlled
by the TU card.
• LED/Alarm Panel, The LED/Alarm panel provides LEDs that reflect the overall
status of the system and an key switch used to acknowledge that a fault condition is
receiving attention.