---
title: "system.serial.readUntil"
description: "Reads a byte at a time from a serial port until a delimiter character is encountered."
---

# system.serial.readUntil

> Reads a byte at a time from a serial port until a delimiter character is encountered.

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

## Description
Reads a byte at a time from a serial port until a delimiter character is encountered. The read will block for up to timeout milliseconds before returning.

If the delimiter is not found before the timeout period, then the buffer will dump, potentially resulting in data loss.

## Client Permission Restrictions
This scripting function has no [Client Permission](projects\project-properties\project-properties.md#client---permissions) restrictions.

## Syntax
`system.serial.readUntil(port, delimiter, includeDelimiter, timeout)`

### Parameters

|Type|Parameter|Description|
|--|--|--|
|String |`port` | The previously configured serial port to use.|
|char| `delimiter` |The delimiter to read until.|
|boolean| `includeDelimiter` | If true, the delimiter will be included in the return value.|
|int| `timeout` |Optional timeout in milliseconds. Default is 5000.|
### Returns
**String** - Returns a String containing all 8-bit ASCII characters read until the delimiter was reached, and including the delimiter if the "includeDelimiter" parameter was true.
### Scope
All