... optical transmission equipment Key words: Optical multiplexer, data transmission equipment, Direct Modulation Optical Transmitter, PDH 16E1 over Fiber Optical Multiplexer Key words: Optical fiber transmission Optical ... wire wrap)Code typeHDB3Other portsAudio 2- line portInput level 0dBr, output level-2dBr,600Ω balancedAudio ... 4- line portInput level -14dBr, output level +4dBr,600Ω balancedRS-232 ...