Sending your STM-1 or E3 over fiber over long distances? Converting Electrical STM-1 to Optical? Extending any of these? We’ve got the solutions for that. STM-1 converter, E3 converter, DS3 converter, all types are here. By the way, these converters sometimes are also referred to as fiber modems, i.e E3 fiber modem, STM-1 fiber modem or DS3 fiber modem.