The FlexWire connector on the FLEX-5000 and FLEX-3000 utilizes the version 1 standard (v1) which is slightly different than the v2 standard used on the FLEX-1500 software defined radio. The major difference is that pin 3 is un-used or physically blocked in the FLEX-5000 and FLEX-3000.
FlexWire v1 connector
The FlexWire v1 connector is a standard DB-9 female connector
Pin 1 - Ground
Pin 2 - Transmit Audio Line Input
Pin 3 - Unused or pin blocked
Pin 4 - PTT Input (Also I2C interrupt request input, if used)
Pin 5 - Ground
Pin 6 - I2C Bus, Serial Clock
Pin 7 - I2C Bus, Serial Data
Pin 8 - +5 Volts DC Out (@ 1 amp)
Pin 9 - Receive Audio Line Output
