Type 10 TARDIS: Used mainly for diplomatic missions, has no weaponry whatsoever. Interior space limited to 10 rooms or so. Chameleon circuit is manually programmed, brakes are left on for dramatic effect, and time travel is enabled. This type of TT Capsule is used by Ambassador Rupert Pink, and his is usually wearing its "Police Box" exterior.
Type 20 TARDIS: Used by the Space Brigade and occasionally the WTPA for interplanetary missions, and is mounted with two light laser cannons. Interior space limited to 10 rooms or so. Lightly armored and without shielding. Chameleon circuit is on automatic mode by default (this is override-able) brakes are left off for stealth, and time travel is only enabled on civilian vessels.
Type 30 TARDIS: Affectionately dubbed the "Battle Box" by Space Brigade pilots, this vessel has 50 interior rooms standard, and unlike other TT Capsules, the console room is usually a few rooms back from the door. Serves as a mobile barracks and is mounted with 10 heavy laser cannons. Heavily armored and shielded. Chameleon circuit automatically disguises itself as an enemy ship or empty space, brakes are left off for stealth, and time travel is disabled for moral reasons.
Type 40 TARDIS: Only one was brought when our ancestors fled Gallifrey. The Lord High President, Teh Doctah, uses it himself. All of the weapons and armor have been removed, although the shields are still in place. The chameleon circuit has been intentionally broken so it is permanently stuck in "Police Box" form. The brakes have been intentionally jammed on for dramatic effect, and time travel is enabled.