ABC Buss General Information
2.8.2012
52-296 Rev B05
Page 25 of 27
AlarmSaf
65A Industrial Way, Wilmington, MA 01887 978 658 6717 www.alarmsaf.com
APPENDIX B, PAGE 2
About the Accessory Board Connector (continued)
Voltage Busses (B1 and B2)
The voltage busses (B1 and B2) are carried on pins 5-8 of the ABC. B1 is the primary voltage,
and should typically be the higher of the two voltages in a dual voltage system. The B1 and B2
(if used) voltages are distributed through the accessory boards connected to the ABC. See the
documentation for the particular accessory boards being used for details on how to utilize the
B1 and/or B2 voltages. Note that 6-pin ABC connectors can carry only the B1 voltage, while 8-
pin ABC connectors can carry both B1 and B2. In order for the B2 voltage to be present, a
second power supply must be included in the system (AC to DC or DC to DC).
CAUTION: If more than one power supply is connected to any of the voltage busses, the
system will not operate properly and damage to the system could occur. Verify that only one
power supply is connected to each voltage buss before powering the system.
Fault Status Buss
The fault status buss carries the DC Fault status between accessory boards and power supplies.
Any product with fault detection and/or reporting capability can report a fault to or from the
ABC chain. Unless otherwise noted in a product’s documentation, AC faults are not transmitted
through the fault status buss.
Some accessory boards have a jumper to split the fault buss. This allows the separation of
faults between two power supplies in some dual voltage systems. If the buss is not split, any
fault on either power supply or any accessory board will show on both power supplies. If the
buss is split, faults on each side of the jumper will go to their respective power supply only,
allowing easier troubleshooting fault conditions, but requiring monitoring of the fault outputs of
both power supplies. Note that only one split should be used in the fault status buss. See the
documentation for the accessory boards in the system to determine which, if any, have a fault
buss split jumper.
NOTE: Not all accessory boards have fault detection or reporting capability; however the fault
status is still carried through these accessory boards to maintain continuity through the chain.
