Transmitting rs485 (2-wire) over multi-mode fiber then back to copper twisted pair. Controling ptz camera. Qustion is do i need a termination point for the dvr, "Speco TN Series in this case" to control PTZ functions i get nothing @ the dvr. Works great when connect direct bypass fiber. i read where one may need 120ohm termination resistor @ Transmitter for dvr to see resistance. Any help??? By the way i am using IFS 1900 series Tranceiver using to fibers.