Figure 2-2. Operator's Controls, Indicators, and Connectors, rear view.

TM-11-6625-3087-12 Frequency Selective Level Meter AN/USM-490 Manual
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TM 11-6625-3087-12

CONTROL, INDICATOR,

FUNCTION

KEY

OR CONNECTOR

Line voltage switch

Used to select 100, 120, 220, or 240 volt operation. Two two-position

switches. Up-up for 100Vac operation, up-down for 120Vac operation, down-up

for 220Vac operation, and down-down for 240Vac operation.

Interface connector

Input and output connector for all external devices. Connector has 24 pins with

metric posts.

Interface control switch

Used to select tracking generator operating mode and address of AN/USM-490.

Seven-position DIP switch. Position one is interface troubleshooting test.

Position two sets tracking generator operating mode. Positions three thru seven

are for address settings.

Fo (0-32MHz) connector

Used for network analysis. Output frequency is 0 to 32.5 MHz and tracks the

front panel displayed frequency. Output power is 0dBm and impedance is 75 .

Leave open for normal use. Connector mates with BNC plug.

10MHZ connector

Used for a signal reference to synchronize external devices to Level Meter

frequency reference. Output power is +8dBm at 50 Leave open for normal

operation. Connector mates with BNC plug.

2-16

Index