---
title: "system.serial.readLine"
description: "Attempts to read a line from a serial port."
---

# system.serial.readLine

> Attempts to read a line from a serial port.

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

## Description
Attempts to read a line from a serial port. A "line" is considered to be terminated by either a line feed ('\n'), a carriage return ('\r'), or a carriage return followed immediately by a line feed.

The function will wait until the timeout period for a terminator. If the timeout is reached before the line is properly terminated, then the buffer will be dumped, possibly resulting in data loss.

## 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.readLine(port [, timeout] [, encoding])`

### Parameters
Type | Parameter | Description 
------- | ------- | ------
String| `port` | The previously configured serial port to use.
Integer| `timeout` | Maximum amount of time, in milliseconds, to block before returning. Default is 5000. [optional]
String| `encoding` | The String encoding to use. Default is UTF8. [optional]

### Returns
**String** - A line of text.
### Scope
Gateway, Vision Client, Perspective Session

## Code Example

```python title="Code Snippet"
# This example will read from the "COM1" port and set the timeout to 10000 milliseconds.
port = "COM1"
timeout = 10000
system.serial.readLine(port,timeout)
```