The powercab does not need any add ons to read and write CVs. There is an auto switch unit that can be added to avoid having to manually switch from the main track to the programming track but it is optional. It's like the Select. In fact I think the auto switch unit can be used with the Select. It's easy to change addresses with the Powercab, just read the manual. Sorry, can't access mine ATM. Edit for typo