Echelon LonWorks Router - Manual (Page 128)

Router Firmware Version
The router firmware version is printed on the label on the memory containing the
router firmware. The label will have a 9-digit part number starting with "726"
followed by a version number. The letters "A," "B," or "C" indicate router
firmware version A, B, or C.
The following figure illustrates the location of the firmware version label for
the RTR-10 Router Core Module.
118 Determining RTR-10 Firmware Version