old electronic components on retro circuit board of a galvanic isolation of data links

16x9 automatic black board brown carbon circuit closeup colored component components copper data design detail device disassembled disposal eco electric electrical electronic electrotechnical electrotechnics electrotechnology engineering environment equipment ewaste galvanic green hardware industrial industry interface isolation isolator link machine metallized network nobody nopeople obsolete ohm old optical optocoupler optoisolator part pcb photocoupler photodiode phototransistor power recycling red resistance resistor resistors retro row separation soldered sorting tech technical technology tin vintage waste white wire