Interlogix VR1900 Series - Manual (Page 4)

VT1900
A Power
A
LED illuminates
A
B
VR1900
B
A Carrier Detect
Power
LED illuminates
1 2
1 2 3
1 2
RS232
ON
RS422
1 2 1 2
RS485
2-WIRE
1 2
RS485
4-WIRE
1 2
NOT USED
NOTE: WITHOUT PROPER FIBER CONNECTION, LED's DO NOT INDICATE
CORRECT OPERATIONAL STATUS OF THE UNIT.