Manual Part 6

DXU-21
1 Product Overview
The DXU-21 is a Replaceable Unit (RU), which acts as an interface between the
transmission network and the transceivers. It also extracts timing information
from the transmission interfaces and generates a timing reference for the RBS.
The DXU also performs supervisory tasks. The DXU-21 transmission interface
has long-haul capability and can be configured to both 1.544 Mbit/s (T1) and
2.048 Mbit/s (E1) transmission interface modes.
1.1 Main Functions
The DXU serves as the Central Main CPU node and its main functions are:
• Provides the RBS with an interface to the transport network through four
E1/T1 transmission ports
• Handles incoming traffic, controls and supervises information and sends
it to its destination within the RBS
• Provides frequency reference signals and timing signals for circuits within
the RBS
• Stores and executes RBS SW stored on a removable flash card
• Controls climate and power systems in non-ECU equipped cabinets
1.2 Variants
The DXU exists in two variants:
• DXU-21
• DXU-21A
The DXU-21A differs from the DXU-21 in the following aspects:
• Battery Mode indicator
• No EOM port and indicator
• No 13 MHz test port
2 Dimensions
The DXU-21 has the following dimensions:
3 (10)
EN/LZT 720 0244 Uen R3A