# UDP Socket

> 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/udpsocket/

_Requires Symcon >= 3.3_

The UDP socket opens an interface which is often used for communication between the gateway/splitter instance and the connected device. It uses the UDP protocol.

### Integration in IP-Symcon

A new UDP socket instance can be created via "+" in the object tree.
The following settings can be made on the configuration page.

| Option                 | Description                                                                                                                                        |
| ---------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------- |
| Open Socket            | Whether the socket should be open or closed.                                                                                                       |
| Send-Host              | Which IP address the data should be sent to.                                                                                                       |
| Send-Port              | On which port the data should be sent.                                                                                                             |
| Receive-Host           | On which TCP interface the data should be listened to.                                                                                             |
| Receive-Port           | On which port the data should be listened to.                                                                                                      |
| Activate Broadcast     | When activated, the UDP socket sends to the broadcast address of the selected Receive-Host interface. The entered Send-Host address is irrelevant. |
| Activate Reuse Address | Allows other programs to listen to the Receive-Port when the "Reuse address" is also activated.                                                    |
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/udpsocket/e2dc6ba8b9-1790424939/io-udpsocket.png)

## USCK_SendPacket

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

`bool USCK_SendPacket(int $InstanceID, string $Text, string $ClientIP, int $ClientPort)`

_Requires Symcon >= 5.0_

sends a string to the I/O

**Parameters**

- `$InstanceID` (int): ID of the UDP socket to be updated
- `$Text` (string): The string to be sent
- `$ClientIP` (string): Recipient's IP
- `$ClientPort` (int): Recipient's port

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

Recipient's port

**Example**

```php
//Sends the packet with the data record "Any data record" on the server socket with ID 12345 to the IP:Port 192.168.1.123:1234
USCK_SendPacket(12345, "Any data record", "192.168.1.123", 1234);
```

## USCK_SendText

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

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

_Requires Symcon >= 3.3_

sends a string to the I/O

**Parameters**

- `$InstanceID` (int): ID of the UDP socket to be updated
- `$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
USCK_SendText(12345, "Any data record"); // Sends the text "Any data record" to the UDP socket with the ID 12345
```