General Description
The LT3000 Series of custom switches offer the ultimate flexibility in system configuration. Optical switches can be combined with a wide selection of other components to match the design requirement of the most demanding applications. Repeatability and reliability are assured by LIGHTech fully developed design and manufacturing system. The LT3000 Series is available with a front panel keypad and a RS232 or GPIB control interface.

FC/APC optical interface. We opened equipment, see last 3 photos, 4x40 switch is made of one 1x40 switch module and one 1x4 switch module inside enclosure, cascaded together. Common port of 1x40 switch and common port of 1x4 switch are optically merged together. 01, 02, …, 40 ports on front panel are output channels of 1x40 switch. COM1, COM2, COM3, and COM4 ports on front panel are output channels of 1x4 switch.

User instruction example to switch on optical path between channel 40 and COM3 port:
At front panel,  insert the fiber end of optical source into port 40, insert the fiber end of optical receiver into COM3 port.
Choose channel 40 of 1x40 switch: Type in: “1” "MRT" on keypad. Type in “40” "ENT" on keypad,  then LCD will show "Switch No.: 001, Channel No.: 040".
Choose channel 3 of 1x3 switch: Type in: “2” "MRT" on keypad. Type in “3”, then "ENT" on keypad,  then LCD will show "Switch No.: 002, Channel No.: 003".
You can also adjust channel number gradually by pressing Up-Arrow key or Down-Arrow key on keypad.

GPIB commands:
To select channel 40 of 1x40 switch: SWITCH:1:40. Then LCD will show "Switch No.: 001, Channel No.: 040".
 To select channel 3 of 1x4 switch: SWITCH:2:3. Then LCD will show "Switch No.: 002, Channel No.: 003".

Our test result shows insertion loss of 4x40 switch is between 1.5dB and 2.9dB at 1550nm,  including 2 FC/APC connector loss. COM3 port has lower insertion loss.