Ken
"Nope", was indeed the correct answer to the question posed, Prodigy and Digitrax throttles are not compatible with each other.
It was your further comments I was referring to:
"all the manufactures hardware is different, the only thing thats the same is the DCC track signal."
One of the superior characteristics of the Lenz system is the sharing of their open architecture, namely the XPressNet used to control the throttles. Also, many DCC systems have Serial/USB interconnections that allow standard inputs to the computer.
A clip from the JMRI website:
XPressNet is the Command Bus used by Atlas, Lenz, ZTC Controls, and Roco. It was developed by Lenz. The XPressNet specification (available from the Lenz website) specifies the electrical communications standards and command set needed for devices to communicate with the command station. While the command stations support the same commands over the XPressNet connection, they do not all use the same connectors. It may be necessary to build an adapter to plug a device into a command station from another manufacturer.
Warm regards to down under!
Joe