All RJ45 bulkhead connectors are straight through...pin 1 to 1 through 8.
A CAT-5 cable to the bulkhead connectors is straight through and will work...as well as CAT-6 etc...that CAT refers to the data throughput capabilities and not the wiring schema.
I want to build a bulkhead connectors that breaks out the headphone/mic jacks so I can either plug a headset into the dash or run it to a wireless transmitter for a cordless headset.
Midland sent me the breakout for the 275...it's the same as the 575 too.
View attachment 376842
-Mac