# Multicast 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/multicastsocket/

_Requires Symcon >= 4.1_

The Multicast 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
The multicast socket can be set up and activated on the configuration page.
Only a click on "Apply" saves the settings and then an attempt is made to establish the connection with activated "Open socket".

![Configuration page](https://www.symcon.de/media/pages/service/dokumentation/modulreferenz/io/multicastsocket/9b56277a1f-1790424939/io-multicastsocket.png)

#### Send-Host/Port
IP and port of the device to be controlled.

#### Receive-Host/Port
Determines on which network and via which IP and port the data is received.

#### Multicast
Multicast group address that is logged on and obeyed.

#### Activatable Options

| Option        | Description                                                                                                        |
| ------------- | ------------------------------------------------------------------------------------------------------------------ |
| Broadcast     | Allows broadcast messages to be sent                                                                               |
| Reuse Address | Allows the socket to be connected to an address that is already in use.                                            |
| Loopback      | Activates the reception of Multicast-Packets on the send socket, provided this is a member of the Multicast Group. |

## MSCK_SendText

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

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

_Requires Symcon >= 4.1_

sends a string to the I/O

**Parameters**

- `$InstanceID` (int): ID of the Multicast Socket to be updated
- `$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
//Sends the string "Any data record" on the Multicast Socket with the ID 12345
MSCK_SendText(12345, "Any data record");
```