# Serial Port

> Symcon documentation · English · generated on 2026-09-26  
> Index: https://www.symcon.de/en/llms.txt

Source: https://www.symcon.de/en/service/documentation/module-reference/i-o-instances/serialport/

_Requires Symcon >= 2.0_

The serial port opens an interface which is often used for communication between the gateway/splitter instance and the connected device.

### Integration in IP-Symcon
The serial port, to which the device to be controlled is connected, must be specified on the configuration page.
If necessary, the baud rate, data bits, stop bits and parity can be set.

Only a click on "Apply" saves the settings and then an attempt is made to establish the connection.

![Configuration page](https://www.symcon.de/media/pages/service/dokumentation/modulreferenz/io/serialport/f3c490abf1-1790424939/io-serialport.png)

## SPRT_SendText

Source: https://www.symcon.de/en/service/documentation/module-reference/i-o-instances/serialport/sprt-sendtext/

`bool SPRT_SendText(int $InstanceID, string $Text)`

_Requires Symcon >= 2.0_

sends a string to the I/O

**Parameters**

- `$InstanceID` (int): ID of the serial port to be updated
- `$Text` (string): The string to be sent

**Returns** (bool): If the command succeeds, it returns __TRUE__, otherwise __FALSE__.

The string to be sent

**Example**

```php
//Sends the text "Any data record" to the serial port with the ID 12345
SPRT_SendText(12345, "Any data record");
```

## SPRT_SetBreak

Source: https://www.symcon.de/en/service/documentation/module-reference/i-o-instances/serialport/sprt-setbreak/

`bool SPRT_SetBreak(int $InstanceID, bool $OnOff)`

_Requires Symcon >= 2.6_

switches the break of a serial port instance

**Parameters**

- `$InstanceID` (int): ID of the serial port to be updated
- `$OnOff` (bool): Switches the break On __True__ or Off __False__

**Returns** (bool): If the command succeeds, it returns __TRUE__, otherwise __FALSE__.

Switches the break On __True__ or Off __False__

**Example**

```php
// switches the break of the serial port instance with the ID 12345 to "On"
SPRT_SetBreak(12345, true);
```

## SPRT_SetDTR

Source: https://www.symcon.de/en/service/documentation/module-reference/i-o-instances/serialport/sprt-setdtr/

`bool SPRT_SetDTR(int $InstanceID, bool $OnOff)`

_Requires Symcon >= 2.6_

switches the DTR of a serial port instance

**Parameters**

- `$InstanceID` (int): ID of the serial port to be updated
- `$OnOff` (bool): Switches the DTR On __True__ or Off __False__

**Returns** (bool): If the command succeeds, it returns __TRUE__, otherwise __FALSE__.

Switches the DTR On __True__ or Off __False__

**Example**

```php
// switches the DTR of the serial port instance with the ID 12345 to "On"
SPRT_SetDTR(12345, true);
```

## SPRT_SetRTS

Source: https://www.symcon.de/en/service/documentation/module-reference/i-o-instances/serialport/sprt-setrts/

`bool SPRT_SetRTS(int $InstanceID, bool $OnOff)`

_Requires Symcon >= 2.6_

switches the RTS of a serial port instance

**Parameters**

- `$InstanceID` (int): ID of the serial port to be updated
- `$OnOff` (bool): Switches the RTS On __True__ or Off __False__

**Returns** (bool): If the command succeeds, it returns __TRUE__, otherwise __FALSE__.

Switches the RTS On __True__ or Off __False__

**Example**

```php
// switches the RTS of the serial port instance with the ID 12345 to "On"
SPRT_SetRTS(12345, true);
```