串口（RS-232 (COM1)，RS-232/Debug Port (COM2/DEBUG)，RS-232/485 (COM56)，Internal RS-232 (COM34)）
From ESS-WIKI
RS-232 (COM1)
RSB-4710 provides one D-Sub 9-pin connector serial communication interface port. The port can support RS-232 communication.
| Pin | Description |
| 1 | NC |
| 2 | NC 2 COM4_RXD |
| 3 | COM4_TXD |
| 4 | NC |
| 5 | GND |
| 6 | NC |
| 7 | NC |
| 8 | NC |
| 9 | NC |
.PNG)
RS-232/Debug Port (COM2/DEBUG)
RSB-4710 can communicate with a host server (Windows or Linux) via a debug cable (Advantech part number: 1700028481-01).
| Pin | Description |
| 1 | NC |
| 2 | COM2_TXD |
| 3 | COM2_RXD |
| 4 | GND |
RS-232/485 (COM56)
RSB-4710 provides a two-port RS-232/458 pin header. Users can configure RS-232/ 485 mode on uboot. The system must be reset after switching to RS-485 from RS[1]232. A cable (Advantech part number: 1700031060-01) can be used for connecting a standard D-SUB 9P connector.
| Pin | Description |
| 1 | COM8_TXD_c |
| 2 | COM8_RXD_c (RS-485 data +) |
| 3 | COM8_RTS_c |
| 4 | COM8_CTS_c |
| 5 | COM8_DCD_c (RS-485 data - |
| 6 | GND |
| 7 | GND |
| 8 | COM9_DCD_c (RS-485 data -) |
| 9 | COM9_CTS_c |
| 10 | COM9_RTS_c |
| 11 | COM9_RXD_c (RS-485 data +) |
| 12 | COM9_TXD_c |
Internal RS-232 (COM34)
RSB-4710 provides a two-port RS-232 pin header that can supply 5V or 12V power via J3 selection.
| Pin | Description |
| 1 | COM6_TXD |
| 2 | COM6_RXD |
| 3 | COM6_RTS# |
| 4 | COM6_CTS# |
| 5 | COM6_PWR |
| 6 | GND |
| 7 | GND |
| 8 | COM7_PWR |
| 9 | COM7_CTS# |
| 10 | COM7_RTS# |
| 11 | COM7_RXD |
| 12 | COM7_TXD |
