Testing Out My Calculator Space Matt Buttons

Although I have not gotten all of the wires from my make shift Space Matt Buttons wired into Molex Connectors yet, almost there just need to get some more 22 AWG wire as I ran out yesterday. I figured I would work out a diagram of how the buttons are configured and what I'm proposing to do with them in regards to using them to cycle through the message in the Message Centre and have then produce a random DTMF tone from the built in tone generator in the Knight Rider World Voice Box (V.B.)

Theoretically I'm thinking this should work based on the instructions that came with the Knight Rider dash electronics. As you can see in my diagram I have combined all of the momentary switch button wires into one wire to ground, they do have the option to be used individually in the future as I have wired them up to the Molex connectors separately. But for my immediate purpose right now just a single ground signal from all of the buttons to cycle through the Message Centre and request a random DTMF Tone from the V.B. will do for now. I know from my test yesterday that the Message Centre will cycle through with a simple Momentary switch. My only concern right now is are the V.B. DTMF Tone Generator and the Message Centre momentary switch options wired the same way?? This is something that needs to be figured out.

NOTE: Today I did a Multi Meter test on both the Message Centre Cycle Connections and the V.B. DTMF Tone Request Connections and get a reading of around 3.9 when set to DC Voltage so I think they are set up the same way as far as input signal.