from top to bottom in the following picture
1. Control Bus Cable with RJ-H connector 4P4C. A 4 wire cable used between boosters and a command station. Maximum length is 300 feet.
2. Coiled Cab Bus Cable with RJ12 connector 6P4C. A 4 wire cable 6 feet long used for tethered cabs. Notice the 6 pin connector with only 4 slots being used. This is a regular Cab cable.
3. Cab Bus Cable with RJ12 connector 6P6C. A flat 6 wire cable used for tethered cabs, UTP panels, the cab bus and the Powercab. For regular cabs the maximum length is 40 feet. When used with the Powercab this cable carries full track power so the maximum length is 8 feet.
* Note a 6P4C or a 6P6C cable can be used with any cab except for the Power Cab.