User`s guide

What is an Attenuator? Getting Started with Attenuator Modules
Agilent 81560A, 81561A, 81566A, & 81567A Optical Attenuator Modules, First Edition 19
Variable Optical Attenuator Front Panels
Agilent 81566A
Figure 4 Agilent 81566A Attenuator with Power Control and Straight Connector
Agilent 81567A
Figure 5 Agilent 81567A Attentuator with Power Control and Angled Connector
Front Panel Controls and Indicators
The front panel contains a push button to switch the shutter
open/closed, and a LED that indicates the state of the shutter. If the
shutter is “open”, the LED shows “enable”, and light can pass through
the instrument.