Yes, Yes, and no
It basically duplicates all the functions of the M-RK on the external control head, believe it or not, it was designed that way......
Although not officially supported, people have been able to 'dual band' an M-rk mobile and a Orion mobile using the 'radio' key, and running a VHF M-rk and UHF Orion, all from one control head..
The normal configuration is TWO Orions and one control head, but since they share similar/the same bus language, you can use it to swap between an Orion and a M-rk in an enhanced vehicular charger...
I LOVE GE, if not for Mark, the 'techie' over at ericsson/comnet/macom/tyco/flavor of the day.. He's a really great guy, and knows his shtuff....
I'm actually transitioning all my stuff over to GE/Ericsson/Tyco/Comnet/Macom/ Flavor of the day...