Homebrew CI V interface not working?

[KD4SBY]

I build the CI V interface from the circuit published by QST in 7/92 by KG7SG to use it with my IC-718  and it does not seem to work with HRD. I can not get any readings from my 718.
Is there any way I can test with the computer or the 718 if the interface is working properly? Any comments?

[AA6YQ]

I build the CI V interface from the circuit published by QST in 7/92 by KG7SG to use it with my IC-718  and it does not seem to work with HRD. I can not get any readings from my 718.
Is there any way I can test with the computer or the 718 if the interface is working properly? Any comments?

Do you have a volt-meter or oscilloscope you can use to verify that the circuit is receiving power from whichever modem control signal (RTS or DTR) you're using as a power supply?

     73,

          Dave, AA6YQ

[KD4SBY]

Dave,
I have -9V on the RTS pin. (Should that not be a + voltage?)

[KD4SBY]

UPDATE - The voltage goes from -9V to +3V when HRD is connecting.
It is not reading the frequency after three tries.