PSSu H FS2 SN SD 312087 Communication modules PSSuniversal I/O, for implementation of safety-related and standard applications in the automation system PSS 4000. PSSu, head module with increased performance, control system PSSu I/O, failsafe and standard, PL e, SIL CL 3, 2 RJ45 ports, SafetyNET p RTFN.