User manual

Wide Bank 28 DS3 - Release 2.4 July 2004 2-7
Product Description
Connector Panel Interfaces

External Clock Connector. An external DS3 clock connector (75-ohm unbalanced BNC) is
provided for clocking the unit from an external 44.736 MHz timing source, when required.
 Alarm Connector. The alarm contacts are on a 4-position wiring block connector. There are
contacts for a critical alarm and for a combined major/minor alarm. The contacts can be
programmed to be normally open or normally closed. One cable connector, which can be wired
to externally-powered alarm monitor or indicator, is provided with each Wide Bank 28 DS3. For
wiring information, see External Alarm Wiring on page 5-12.
 Power Connectors. Power connections are made to the –48 VDC power connector input with a
three-position removable wiring connector. An 8-foot DC power cord is provided with each
Carrier Access Corporation 120 VAC to –48 VDC Power Converter/Battery Charger. There are
two independent power receptacles on the rear of the Wide Bank, labeled A and B. Power
connector A supplies –48 VDC to the power supply on Controller card A, and power connector B
supplies –48 VDC to the power supply on Controller card B. For wiring information, see Wiring
the Power Plugs on page 5-14.
The Controller cards are designed to provide power to each other if a power failure occurs. If only
power connector A has a power source plugged into it, the power converter for Controller card A
will supply power to the entire system including Controller card B. However, if Controller card A
is removed, Controller card B will no longer receive power. The same is true (in reverse) if only
power connector B has a power source.
WARNING! FOR REDUNDANT OPERATION BOTH CONTROLLER CARDS MUST
RECEIVE POWER AND BOTH POWER CONNECTORS MUST HAVE A POWER SOURCE
PLUGGED INTO THEM. IT IS RECOMMENDED, AND IS STANDARD PRACTICE, THAT THE
TWO –48V POWER SOURCES BE INDEPENDENT TO MAINTAIN PROPER REDUNDANCY AND
PROTECTION.