What this front connector does in an S7-300 rack
The Siemens 6ES7922-3BF00-5AC0 is a 40-pole front connector with a 5 m pre-wired cable of single cores, designed for SIMATIC S7-300 digital I/O modules. It mates with the 6ES7392-1AM00-0AA0 connector on the module face, giving you a ready-to-terminate wiring harness that runs directly to the field devices. Each core is 0.5 mm² H05V-K, numbered consecutively 1 to 40, and the cable sheath is blue PVC with a 2.2 mm outer diameter per bundled core. The screw-type terminals on the enclosure side accept the stripped wire ends — no special crimp tool needed.
Voltage ratings and signal suitability
Rated at 24 V and maximum 30 V, this connector is built for the 24 VDC nominal supply common on S7-300 digital I/O cards. The 30 V ceiling covers the typical tolerance band for industrial power supplies without derating. The assembly is explicitly suited for digital signal transmission, not analog. If you need to pass analog signals through the same connector, you would need a different variant — this one is for discrete I/O only.
The 5 m cable length gives you enough reach to route from the module slot in the rack to a terminal block or junction box inside the enclosure. The 40 single cores are bundled but not jacketed as a multi-conductor cable — each core is individually numbered and can be fanned out to separate terminals. The blue RAL 5010 cable sheath is standard for Siemens I/O wiring.
The 6ES7922-3BF00-5AA0 is a similar variant, but no direct replacement claim is documented.