Dymec models 5843 and 5844 are hardened fiber optic Link/Repeaters that convert RS232 or TTL levelcopper to amplitude based fiber output. 5843 and 5844 Link/Repeaters support data rates from dc to 250k bps, DCE or DTE port configuration and a diagnostic/test mode that allows testing of the copper and fiber connections before the connected IED is active in the network.