NEC Xen Master System Hardware Manual page 125

System Hardware Manual
3.1.4 Connectors
Before programming System Data, the battery must be
connected to CN4 to allow memory retention if a power
failure or brownout occurs. If a brownout or power failure
does occur, and the battery backup circuit is not activated,
System Data resets to the default values, all stations in the
system reset to the default values, and any data
programmed on individual stations is cleared.
When a CPUB( )-U13 ETU is installed in the system, the
clock/calendar must be set. This also applies when battery
backup fails for any reason.
If the CPUB( )-U13 ETU is removed for long term storage,
disconnect the battery from CN4. This prevents the battery
from discharging completely. The fully charged battery
retains memory for approximately 21 days.
The following connectors are located on the CPUB( )-U13
ETU.
✆
CN1
✆
CN2
✆
CN3
✆
CN4
✆
CN5
✆
CN6
3.1.5 LED Indications
LED1 indications are listed below.
✆
Blinking Red
✆
Steady Red
✆
Off
LED2 indications are listed below.
✆
Steady Red
✆
Off
Connects to the backboard
Connects to the ISA-bus.
Connects to CN2 on the EXP-U13 ETU
via the expansion cable
Connects to the memory backup battery
via the battery cable (factory installed)
Connects to CN1 of the CLKG-U13 Unit
Connects to CN2 of the CLKG-U13 Unit
Normal Operation
Operation Stopped (power still on)
No Power
System Power On
No Power
May 2001
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