OPTICAL REPEATER FOR THE TRANSMISSION OF SERIAL DATAS VIA TWO SINGLEMODE FIBER CABLES FOR SIPROTEC-RELAYS, COMMUNICATION ACCESSORIES 7XV5 AND SERIAL DEVICES UP TO 4.096 MBIT/S, 1550NM, LC-DUPLEX CONNECTOR, PERMISSIBLE ATTENUATION 43 DB (0.25DB/KM) FOR REACHES UP TO 170 KM