MINI-LINKEandEMicro
3.9.2.6 1+1 Protection Switching
In protected operation, the switching logic controls transmitter and receiver
sw itching for the protected radio section.
The selection is controlled and monitored locally or remotely.
The Switch Multiplexer Unit (SMU) contains all switch logic circuitry for
protected systems.
Transmitter Switching
Transmitter selection only applies to hot standby systems. S election is based
on alarm infor mation from the transmitter section of t he radio unit or the MMU.
Selection can also be made manually from the MMU front or from a PC. An
alar m with high pr ior ity overrides an alarm with lower priority. The radio unit
with the lowest priority alarm transmits the signal. See Section 6.1.4.1 on page
97 for a description of the alarms.
Table 1 Prior ity for transmitter switching
Transmitter switching
criteria
Alarm Priority
Switching due to hardware failure
Manual switch mode
1
MMU does not exist NCC Ra
2
CSS fail MMU Proc. Hardware
Proc. Software
EEPROM
3
RAU Proc. Hardware
Proc. Software
EEPROM
RCC
TX High priori ty RCC & Radio Frame
Mod Index
TX IF Input
RF Output Level
4
TX Low priority Input BB1, BB2
(1)
Input E1:1 – 4 (MMU)
5
(1) No switching for BB2 alarm, wayside channel, 17x2 and 34+2 (applies to CSS version 5.0 or
later)
Alar m information from the transmitting side is collected in the Control and
Supervision processor in each MM U and sent to the Switch Logic in the SMU.
The signal is sent to the Radio Unit (RAU) to control the transmitter O n/Off
function.
58
AE/LZT 110 2012 R8C 2002-03-04
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