Pin |
Pin Name |
Description (may be empty) |
1 | DCD | |
2 | TX | |
3 | RX | |
4 | DTR | |
5 | GND | |
6 | DSR | |
7 | ||
8 | ||
9 | +12V | +12V if 1,4 and 6 are shorted |
PC toggles a bit on the DTR line and check the DSR and DCD lines. If the lines are shorted, pin 9 (normally RI) is used to provide 12V power. See patent for more information