---
title: "Bi-directional RS-232/422/485 port"
canonical: "https://docs.cuesystem.com/space/PRODUCTS/297598994/Bi-directional%20RS-232%2F422%2F485%20port"
format: markdown
---
These bi-directional serial channels are used for RS-232, RS-422, and RS-485 communication.

The parameters are as follows:

- RS-232/422/485 modes
- Baud rate can be set to the following values: 300, 600, 1 200, 2 400, 4 800, 9 600, 19 200, 38 400, 57 600 and 115 200 Bd (bps).
- The default mode for all channels is RS-232, other modes must be set in the programmed application. For more details see the programming manuals.

# RS-232 Mode

Output signal levels for RS-232 are in the -10 V to + 10 V range. This is the default mode for all channels.

|  |  |  |  |  |
| --- | --- | --- | --- | --- |
| 5-pin 3.5 mm | Pin | Signal | Description | Direction |
| ![image](media://23baac39-90b4-4d66-acfa-9ab2787d16f0) | 1 | TxD | RS-232 Transmitted Data | From the unit |
| 2 | RTS | RS-232 Request to Send | From the unit |
| 3 | GND | Ground |  |
| 4 | RxD | RS-232 Received Data | To the unit |
| 5 | CTS | RS-232 Clear to Send | To the unit |

# RS-422 Mode

This mode must be set in the programmed application. 

|  |  |  |  |  |
| --- | --- | --- | --- | --- |
| 5-pin 3.5 mm | Pin | Signal | Description | Direction |
| ![image](media://23baac39-90b4-4d66-acfa-9ab2787d16f0) | 1 | Tx A+ | RS-422 Transmit Data (Idles High) | From the unit |
| 2 | Tx B- | RS-422 Transmit Data (Idles Low) | From the unit |
| 3 | GND | Ground |  |
| 4 | Rx A+ | RS-422 Receive Data (Idles High) | To the unit |
| 5 | Rx B- | RS-422 Receive Data (Idles Low) | To the unit |

# RS-485 Mode

This mode must be set in the programmed application.

|  |  |  |  |
| --- | --- | --- | --- |
| 5-pin 3.5 mm | Pin | Signal | Description |
| ![image](media://23baac39-90b4-4d66-acfa-9ab2787d16f0) | 1 | A+ | RS-485 Data + |
| 2 | B- | RS-485 Data - |
| 3 | GND | Ground |
| 4 | N.C. | Not Connected |
| 5 | N.C. | Not Connected |