The original tuner package from Empeg Inc. included nearly zero documentation, so you are not missing anything of note. The numeric wheel on the module is used to give the tuner a unique ID number, theoretically to allow some non-existent software feature the capability to use different audio/tuner settings based on which sled (and therefore which tuner) your empeg player might be connected to at any point in time. This is potentially useful for folks who swap their player between multiple vehicles, each of which has its own tuner module, and with each tuner module set to use a different ID from the others.

This feature does not exist.

The only use for the tuner ID today is that Hijack can use it to distinguish between car and home mode, automatically forcing AC or DC power (and related audio/eq settings) based on the tuner ID.

At some point Real Soon Now, Hijack may also provide tuner ID macros for config.ini, allowing a few more settings to be tweaked automatically based on the ID of a connected tuner, or lack of a connected tuner. But only if more than one person has a real need for this.

Cheers