Looking for some information on this INPUT to MSD Atomic LS (see page 17 of install document, https://documents.holley.com/2950.pdf) where it notes the following:
Calibrate Speed: If there is speed output on the transmission, a reference signal can be delivered to the Atomic
LS. On manual transmission equipped vehicles, the Calibrate Speed option improves driveability when
transitioning from high RPM conditions to an idle (such as coming off of a hill/between moving and
coming to a complete stop). The Power Module has a Brown (Pin D) wire and a Light Blue (Pin E) wire.

These wires connect to a magnetic pickup monitoring driveshaft speed with a collar mounted on a yoke. To
program the calibration, drive to 40 MPH on an open road to maintain speed. Once at 40 MPH, select YES
on the handheld. This will calibrate the speed input. This option will also enable a speedometer reading in
the handheld Atomic LS Dash (Figure 22).

Note: Use of a minimum four magnet collar is recommended with this option.
Pin D : Brown : Speed Ref.
Pin E : Lt Blue : Speed Signal

Questions:
1) What type of "reference" signal is this input looking for? Magnetic, two wire sounds like analog, not digital?

2) What would be a viable (four magnet collar) sensor to purchase that will work in this case? Link would be great!

3) Vehicle in question has Dodge Viper (2000-2005, I think) 6 speed manual transmission and OEM VSS, can that work with this INPUT?
I'm told it was connected, but the handheld always displays 0 MPH in the Atomic Dash display.

The issue with vehicle is with stalling, and surging on DECEL/COAST when returning to idle. Engine is LS3, drive-by-cable. Thanks in advance!