Look here for information about REM_SYS symbolic FRU.
A problem has occurred in a remote system that is in an IBM® i HSL OptiConnect loop.
If the value of the first half of word 7 in the reference code is greater than or equal to 0680, this value is the hexadecimal RIO/HSL loop number. The service action log (SAL) code will attempt to identify the RIO/HSL loop number of the local system and the serial number of the remote system as a portion of the part description for this symbolic FRU. If the SAL could not identify the serial number of the remote system, check all the systems which are connected to the local RIO/HSL loop identified in the reference code or the SAL. Search the SAL of the remote system(s) for hardware and Licensed Internal Code problems. Correct any problems you find with Licensed Internal Code or Network Interface Controller (NIC) / RIO controller hardware.
This ends the procedure.