Ethernet PHY usage (if relevant)
Level-shifter / IO buffer usage
Search for "S4LV02 configuration" in the OEM’s support portal. If this chip is on a board from Siemens, Wago, Beckhoff, or National Instruments, you need their specific hardware manual, not the PHY datasheet. ksz80 ob s4lv02 datasheet
OEMs sometimes disable standard JTAG or MII pins. The "S4LV02" might refer to a custom OTP (One Time Programmable) configuration loaded during manufacturing. In this case, the electrical characteristics, register maps, and timing diagrams are identical to the KSZ8081 datasheet. Only the strapping options (PHY address, LED modes) differ. Ethernet PHY usage (if relevant)