Getting RPM (WITHOUT an ECU)

[Holmz]

I want to get an PRM logged into an ACL, and I have aVIM, but no ECU nor CAN connections that I can use for (or from) the engine.

Can something like this be used to get RPM pulses into a VIM, so that I can get them into an ACL?
http://www.msdignition.com/product.aspx?id=4721&terms=8918

It apparently has 3 wires:
1) 12v switched
2) Ground
3) Green = signal

With a 12v pulsing power line going under the magnetic tab (ignition-to-coil or FI) and then the green wire doing a square-wave (pulse) at 12v according to tech support at MSD.
But my confidence in their tech support was <100%
I did find a .pdf for the device at the link under the "downloads" tab...

Can anybody confirm or suggest other known options?

[synapse]

Is this on a car? One would think that you could just pick up the RPM from the igniter, or mag pickup if this is a carb/non-ecu car. If it has an ECU, you could go straight to the cam angle sensor.

[Holmz]

Is this on a car? One would think that you could just pick up the RPM from the igniter, or mag pickup if this is a carb/non-ecu car. If it has an ECU, you could go straight to the cam angle sensor.

Thanks Synapse.

Yup it is on a car.
I picked up the MSD unit months ago, but have not gotten around to hooking it up yet.
And I probably will just go straight to an ECU as I have a new engine that is coming together - and going together slowly applies to that as well as everything else.