[Elecraft] K3 Interface to Key a Collins 30L-1

[Bill]

The Collins 30L-1 keying line  =  -170 Volts at 80 ma.
 
This will blow up the keying circuit in the K3 if connected directly
 
What you need:
 
http://www.wb9kzy.com/keyall.htm
 
cheap, easy, works well.....
 
Bill - K6WLM
 
KX1, K2, K3-100