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3 Board
DIP Switch
or Jumper
SW6-1
SW6-2
SW6-3
SW6-4
J18
3.21 TMU
3.21.1 Functions
The TMU is the entity in charge of the BTS timing, transmission and management.
It has the following functions:
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3.21.2 Structure and Principle
Figure 3-45
and the EAC.
3-68
Function
Resistance setting of the first E1
Short-circuiting 1–2 is 75 ohms, and 2-3 is
120 ohms.
Resistance setting of the second E1
Short-circuiting 1–2 is 75 ohms, and 2–3 is
120 ohms.
Resistance setting of the third E1
Short-circuiting 1–2 is 75 ohms, and 2–3 is
120 ohms.
Resistance setting of the fourth E1
Short-circuiting 1–2 is 75 ohms, and 2–3 is
120 ohms.
Order wire feeding voltage setting;
Short-circuiting 1–2 is –24 V DC, and 2–3 is
–48 V DC.
The hardware version of the TMU described in this section is REV.C and for the previous version, the
introduction will be based on the description of REV.C in this section.
Supporting multi-channel multiplexing, which furthers the utilization of the limited
transmission resources;
Supporting flexible topology modes, including star topology, tree topology and chain
topology of BTS;
Providing MMI and O&M link, and realizing software downloading, fault management,
configuration management, performance management and security management;
Providing the centralized provisioning and hot backup of the clock;
Providing the input port for external alarm signals and collecting the external alarm.
shows the system structure of the TMU, including the BIU, the OMU, the MCK,
Huawei Technologies Proprietary
M900/M1800 BTS3X Series Base Transceiver Station
Hardware Description Manual
Default
Setting
1–2
1–2
1–2
1–2
2–3
Issue 01 (2006-11-18)
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