This forum is dedicated to discussions pertaining specifically to the Motorola ASTRO line of radios (those that use VSELP/IMBE/AMBE), including using digital modulation, digital programming, FlashPort upgrades, etc. If you have general questions please use the General or Programming forums.
You require the ASTRO25 Mobile CPS. It will program the Digital Spectra Plus, and the XTL5000. It may also program the XTL2500/XTL1500 series--that's unconfirmed.
I believe the programming cable is the 3085001D01 digital is the same one that's used with the digital spectra plus. Someone will correct me if I'm wrong.