| Pin No. | RS-232 Signal | RS-485 Signal | Current Loop Signal |
|---|---|---|---|
| 1 | DCD | RxD B(+) | RxD(-) |
| 2 | RxD | TxD B(+) | TxD(+) |
| 3 | TxD | TxD A(-) | TxD Source |
| 4 | DTR | RxD A(-) | TxD Return |
| 5 | SG | SR | SG |
| 6 | Reserved | CTS A(-) | RxD Return |
| 7 | RTS | RTS A(-) | TxD(-) |
| 8 | CTS | RTS B(+) | RxD(+) |
| 9 | Reserved | CTS B(+) | RxD Source |
Male DB-9 Connector
