Inside the unit, there is one 1X3 (3 pin) header block which is set to select the pin 9 of DB-9 male connecter. You need to push down the upper case, and slide it open by following the direction of the arrow in the illustration below. You can set the jumper to provide the pin 9 of DB-9 male connecter for RI signal or DC 5V 150mA power.
Pin 1 | DCD |
Pin 2 | RxD |
Pin 3 | TxD |
Pin 4 | DTR |
Pin 5 | GND |
Pin 6 | DSR |
Pin 7 | RTS |
Pin 8 | CTS |
Pin 9 | RI |
Pin 1 | DCD |
Pin 2 | RxD |
Pin 3 | TxD |
Pin 4 | DTR |
Pin 5 | GND |
Pin 6 | DSR |
Pin 7 | RTS |
Pin 8 | CTS |
Pin 9 | DC 5V |