User Manual

Node B Installation Guide
DRAFT
17 July, 2001 IPWireless Proprietary
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17
4.5 (Step 9) External Alarms
If local alarms are to be utilized for a terminal block has been provided on the Node B
termination panel. The specifications for those interface requirements are below.
4.5.1 Alarm Input Specification
The alarm inputs from the Node B Patch board to the digital board shall be TTL levels and active
high.
The external alarm inputs shall be opto-isolated current loops.
The voltage and currents shall be supplied by the external source.
4.5.2 Alarm Output Specification
The alarm outputs from the digital board to the Node B Patch Board shall be TTL levels and
active high. .
The external alarm outputs shall be isolated normally-open relay contacts capable of switching at
least 100mA DC.