The 236-ILC-3 is a cable from Keithley.
The Keithley Model 236-ILC-3 is a 3-pin female to 3-pin female interlock cable assembly for the 236, 237, 238 and the Model 4200-SCS. The cable is 9.8 ft (3 m) long.
The Model 236-ILC-3 cable connects the safety interlock circuit of the Model 4200-SCS to the safety interlock switch of the test fixture containing the device under test. To use the Model 236-ILC-3, plug one end of the cable into the INTERLOCK connector on the test fixture, and connect the other end of the cable into the INTERLOCK connector on the rear panel of the instrument.