The XTS Series covers the XTS3000/XTS3500/etc. Since the XTS radios are ASTRO capable, you may want to look at the ASTRO Portable Page.
Click here to see the programming cable schematic.
If you want to take these radios out of band, see the out of band information on the Astro Saber page. It should be the same.
If you are looking for information on the XTS Vehicular Adapter, the XTVA, click here.
Here are a listing of the Service Manual part numbers for this series of radio: