alt Hacker NewsEvery vendor defines their audio jack connector serial port differently. It is very dangerous to use 3.5mm jack. There is no pinout standard of using 3.5mm.
Even as pure audio jack, the 3.5mm connector has two standards, with the difference on ground and mic.
Well, not every vendor does it differently, because there are far more vendors than possible wiring permutations on a 3-contact connector... but I understand what you mean.
The same issue applies to PCB header pins.
And the same goes for 25-pin D-sub connectors, which have been widely used as RS-232, parallel printer, and SCSI ports.
Voltages vary, too.
This is why we check before wiring them to other things.