ALL DCC cables are data cables. They are NOT analog phone cables. The connections on both ends are passthrough, not crossover. This means the colors and pinouts are 100% identical. Not using the correct cable will cause instant damage to the connected equipment. The few dollars in savings are not worth the risk and time wasted. Only use NCE cables. The size of the individual wires in the cable is a major factor in choosing the correct cable. This is especially important for the Power Cab, where the 6-pin cable also carries track power. Using smaller gauge wire has a DIRECT impact on track power!
From left to right in the picture below:
1. Cab Bus Cable with RJ12 connector 6P6C. Needed for Power Cab to provide track Power. It can also be used for any other Cab Bus connection. Six 24awg conductors.
2. Cab Bus Cable with RJ12 connector 6P4C. No track power connections.
3. Control Bus Booster Data Cable with RJ-H connector 4P4C.
1. Cab Bus Cable with RJ12 connector 6P6C. A flat 6-wire cable is used for tethered cabs, UTP panels, the cab bus, and the Power Cab. For regular cabs, the maximum length is 40 feet. When used with the Power Cab, this cable carries full track power. The maximum length is 7 feet in this usage.
2. Cab Bus Cable with RJ12 connector 6P4C. A 4-wire coiled cable 6 feet long is used for tethered cabs. Notice the 6-pin connector with only 4 slots being used. This is a regular coiled Cab cable. No track power. One length only,
3. Control Bus Booster Data Cable with RJ-H connector 4P4C. A 4-wire cable is used between boosters and a command station. Maximum length is 300 feet.
The two outer wires (white and blue) on the six-wire cable are used to provide the track power output of the Power Cab. The rest of the time, the two outer wires are not used at all. That includes using it for the cab bus, RB02, and the direct connection from the RB02 to the RPT1.
For the record, I am NOT a fan of telco splitters. They can and DO fail. I have taken MANY calls where the source of problems was traced back to poor-quality analog phone cables and splitters. Do not use them. They are not designed for data cables. They must be of the 4-wire variety and NOT have flipped or swapped colors. Use these at your own risk.
The end result is all that matters. You need clean data on pins 3 and 4 (red /green). You need a minimum of 8vdc / nominal 12vdc on pins 2 and 5 (black and yellow).