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I'm guessing it's a way to decouple the electrical connection between the audio system and the phone, to prevent the propagation of GSM/cellular radio noise.
by jasongullickson 16y ago
I'm guessing it's a way to decouple the electrical connection between the audio system and the phone, to prevent the propagation of GSM/cellular radio noise.
- jrockway 16y agoThat is what optoisolators are for, but they wouldn't help with GSM noise. (GSM noise is related to the fact that GSM divides the radio spectrum into time slices for devices to use to talk to the tower. When a phone gets its time slice, it turns the radio on. When the timeslice is over, the radio is turned off. The time slices come in intervals that are in the audio range, and thus its energy output is measurable in the audible range. Since the radio signals will induce a current in random wires, including wires in your audio amplifier, you can hear the GSM noise in your speakers. It is not related in any way to an unclean audio signal coming out of your phone; that signal has no GSM noise. It's the radio communication that induces noise in your audio equipment. So a speaker + microphone is not going to do anything except make your already-clean audio sound like shit.)