RM-UC1 connector (from: https://www.doc-diy.net/photo/remote_pinout/ )

This is the plug found on the Olympus RM-UC1 remote release. According to the Olympus web site it fits the models:
E-P1, E-P2, E-P3, E-P5, E-PM1, E-PL2, E-PL3, E-30, the E-400 series, E-510, E-520, E620, OM-D E-M1, E-M5, EM10, etc.

It's also compatible with the compact cameras: XZ-1, SZ-20, SZ-30 MR, SP-565, SP-570 and SP-590.