- Our E-2000® HRL category 0. 1 dB is a singlemode APC 8° fiber optic connector with solid-ceramic ferrule for all singlemode applications with particularly high requirements on optical transmission quality and protection of the connector ferrule, e. metropolitan (MAN) and. The E-2000™ connector is the most mechanically robust FO connector. Combined with R&M's quality requirements for raw materials, design, and workmanship, it guarantees the most stable transmission performance over the entire 25-year system warranty. The connector lever is a. Our DTMH and DTM EE04 modification connectors are environmentally sealed and engineered to operate in high temperatures from -55°C to +150°C.