What this firmware package does on the S7-300 rack
The 6ES7357-4BH03-3AE0 is a firmware LX delivery package — a memory card and CD — for the Siemens FM357-2 positioning module on the S7-300 platform. It provides the configuration and runtime firmware for multi-axis positioning and path control of stepper and servo motors. This is not a hardware I/O module; it is the software layer that turns the FM357-2 into a motion controller. The form of delivery — memory card plus CD — means the firmware is pre-loaded onto the card and the CD holds the configuration package for the engineering station.
Lifecycle reality — eol_hot and what it means for procurement
For a line that depends on the FM357-2 firmware, this status flags a last-time-buy window that has already closed.
What is actually in the box
The delivery contents are a memory card carrying the firmware LX and a CD with the configuration package. The firmware LX is the licensed runtime for the FM357-2; the configuration package is the engineering tooling needed to set up axis parameters, cam profiles, and path programs. Because this is firmware tied to a specific hardware module (FM357-2), it is not a general-purpose S7-300 firmware update. It applies only to the positioning and path-control function of that module, for stepper and servo motor axes.