... one coaxial cable video multiplexer with RS485 usded in CCTV Maintenance SD-S803VCS/R4CH video/3CH ... video+1CH negative data1,as project demand,the device is optimized interface,and is convenient for ... delay and disturbances;5,adjustable knob is installed in receiver,which can fine adjustment transmssion distance, ... different camera;7,12V DC power supply,built-in;8,all ports use high quality IVXBNC ...