Cisco Systems Cisco 12008 manual Source DC Input Connectors

Overview of the Cisco 12008

The three contacts on the alarm terminal block are labeled as follows:

•COM (Common)—This contact is common to both the Normally Open (NO) and the Normally Closed (NC) contacts.

•NO (Normally Open)—These contacts on the alarm terminal block are open as long as no overcurrent condition is detected in the power supply. When the power supply circuit breaker is tripped during an overcurrent condition, these contacts are closed.

•NC (Normally Closed)—These contacts on the alarm terminal block are closed as long as no overcurrent condition is detected in the power supply. When the power supply circuit breaker is tripped during an overcurrent condition, these contacts are open.

Table 1-1 summarizes the status of the contacts on the alarm terminal block during an overcurrent condition in the power supply.

Table 1-1	Circuit Breaker Status Indicated by the Alarm Terminal Block
Circuit Breaker Position		NC Contact	NO Contact
OFF (tripped)		Open	Closed
ON		Closed	Open

If you decide to use an external alarm-monitoring facility in conjunction with the alarm terminal block, note that the contacts on the alarm terminal block have a rating of 60 VDC at 1A maximum.

Source DC Input Connectors

The faceplate of the DC-input power supply incorporates three sets of terminals for connecting source DC power to the power supply (see Figure 1-7). From top to bottom, these terminals are identified as follows:

•

•

•

Ground

+(positive)

–(negative)

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