You can use the Keithley Instruments connector CS-1616-3, supplied 
with the Model 2461, to make the interlock connection to the rear 
panel. You must supply connection wire. 
To ensure proper interlock operation, the external interlock switch 
and connection wires must be less than 10 Ω when the switch is 
closed. 
 
The pin locations and connections are shown in the following figure. 
The pins are: 
  Pin 3: Earth and chassis ground 
  Pin 2: Interlock 
  Pin 1: +6 V DC out (current limited) 
 
 
 
For the examples shown in this quick start guide, you do not need to 
use an interlock. The Model 2461 functions on all current ranges and 
up to ±42 volts without asserting the interlock.