[Yaesu] FT-2400 & FT-2500 PTT Control

[John Graves]

I have a FT-2400 that I am trying to interface to a computer for an 
echolink access.  The manual says that Pin 3 on the Mike jack is PTT and 
Pin 5 is ground.  I constructed a transister switch to pull Pin 3 to 
ground and go to transmit when DTR goes high  It doesn't work, although 
I can measure that with a DTR Voltage on the switch, it goes to ground. 

As a test, I made a jack with Pin 3 looped to Pin 5.  If I insert it in 
the jack,  the rig still stays in receive.  What am I missing?

John / WA1JG