---
title: "system.serial.write"
description: "Write a String to a serial port using the platforms default character encoding."
---

# system.serial.write

> Write a String to a serial port using the platforms default character encoding.

This function is used in **Python Scripting**.

## Description
## Client Permission Restrictions
This scripting function has no [Client Permission](../../../ignition-modules/vision/vision-project-properties/vision-project-properties.md#vision-permissions-properties) restrictions.

## Syntax
`system.serial.write(port, toWrite, [timeout], [encoding])`

### Parameters
Type | Parameter | Description 
------- | ------- | ------
String| `port` | The previously configured serial port to use.
String| `toWrite` | The String to write.
Integer| `timeout` | A timeout, in milliseconds. Writes exceeding this period will . Defaults to 5000 [optional]
String| `encoding` |Encoding to decode the string with, for example: UTF-8. Default is the platform default character set. [optional]

### Returns
Nothing
### Scope
Gateway, Vision Client, Perspective Session

## The encoding Parameter
The encoding parameter can  be used to decode a string with any of the possible encoding character sets that are available. By default, the following character sets are provided by the [Java platform](https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/nio/charset/StandardCharsets.html) (dash characters and underscores are interchangeable). Dashed examples are shown below:

* ISO-8859-1
* US-ASCII
* UTF-16
* UTF-16BE
* UTF-16LE
* UTF-8

## Code Example
```python title="Code Snippet"
# This example will write a string to a port called "COM1".
port = "COM1"
toWrite = "I am a string"
 
system.serial.write(port,toWrite)
```