Well I won't argue that I'm old and dense. However most of the things posted are like upper level algebra and I'm hoping for a basic arithmetic class. Fortunately I can get by with downloading the "needed stuff", but I'm struggling with what it all means, such as color codes and the like.
Colour codes are similar in function to what a NAC does on P25. They are a method to filter signals, when you can hear more than one DMR repeater on the same frequency. I believe there are 16 colour codes.
Group Calls, aka, Talkgroups are the same as what you find on trunk systems. Talkgroups can also be used on conventional DMR, to separate multiple users on one repeater.
Groupcalls can also be used on simplex as well.
DMR also has provisions for individual calls, radio to radio.
DMR also has provisions for SMS like messaging, and there are also developers that have written software to allow the GPS units found in Hytera and Motorola radios send data and have it plotted on maps.
Slots are Time Slot 1 and Time Slot 2(TS1&TS2 or TS0&TS1). A single repeater can hold 2 voice calls at the same time. This is accomplished by the subscribers(mobile and portable radios) rapidly keying and un-keying. When user 'a' is transmitting, user 'b' is not. When user 'b' is transmitting, user 'a' is not ect. This occurs very rapidly, approximately every 30ms(I think it is 30ms, not 100% sure on the actual time) the radio will key then un-key, with the other user keying on the 30ms the first user is not transmitting. This is called Time Division, Multiple Access. P25 phase 2 radios operate in a similar fashion.
Hopefully this helped. If you have any questions feel free to ask.