8163A/B, 8164A/B, 8166A/B User’s Guide 219Setting Attenuation and/or Power Levels 8Power UnitsTo select the units used to display power values:1 Use the Cursor key to highlight a power parameter (P set or Pref ), thenpress the [Pwr Unit] softkey.2 Select <W> or <dBm>.3 Press [OK].The menu item <Power Unit> is functionally equivalent to the[Pwr Unit] softkey.How to Control the ShutterThe optical path of the Attenuator module is controlled by a shutter, whichyou can use both for protection purposes or to simulate channel drops.When the shutter is open, the green LED on the attenuator module’s frontpanel is lit.The Enable buttonPress the Enable button, located on the front panel of the Attenuatormodule, to toggle the shutter state.The On/Off SoftkeyPress the [On/Off] softkey to toggle the shutter state.The menu item <Output State>, and the parameter [Output], is functionallyequivalent to the [On/Off] softkey.Output at StartupTo select the shutter state at startup:1 Press the [Menu] softkey.2 Use the Cursor key to highlight <Output at Startup>, then press Enter.3 Select <Off > or <On>.4 Press [OK], then press [Close].Remote InterlockThe Attenuator module’s shutter state is protected by mainframe’s RemoteInterlock (RIL) feature. The shutter cannot be opened if the 50W resistor isremoved from the RIL connector on the back panel of the mainframe. SeeThe Remote Interlock (RIL) connector on page 337.
