Ericsson MINI-LINK TN R4 ETSI Technical Description page 36

Technical Description
3.6.2.1.4 Power
This block interfaces the Power bus and provides secondary voltages for the
unit. All plug-in units have a standard power module providing electronic soft
start and short circuit protection, filter function, low voltage protection, DC/DC
converter and a pre-charge function.
3.6.2.1.5 VC-12
This block maps 63xE1 (or 21xE1) to/from 63xVC-12 (or 21xVC-12) adding
overhead bytes.
The LTU B 155 registers 21xE1 interfaces from the first TUG3, that is the KLM
numbers 1.1.1-1.1.3, 1.2.1-1.2.3 through 1.7.1-1.7.3.
3.6.2.1.6 MS/RS VC-4
This block maps the VC-12s to/from one VC-4 adding path overhead.
The block provides the electrical and optical STM-1 line interfaces for external
connection.
3.6.2.1.7 SDH Equipment Clock
This block handles timing and synchronization.
The LTU 155 utilizes the synchronization functions described in Section 3.11
on page 60.
3.6.3 SXU3 B
SXU3 B is an SDH Add-Drop Multiplexer and supports Ethernet over SDH (up
to 600 Mbit/s) and PDH over SDH (mapping of 21xE1 to/from VC-12s).
The SXU3 B fits in an AMM 2p B, AMM 6p C or AMM 6p D, and it provides 4
additional E1 interfaces on the front.
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