Node Serialport

For support you can open a github issue, for discussions, designs, and clarifications, we recommend you join our Gitter Chat room. We have two related projects Browser Serialport "just like Node Serialport but for browser apps", and Serialport Test Piliot which helps us test serialport.

If you'd like to contribute please take a look at contribution guide and code of conduct. You also might want to see the road map. We also have issues tagged "good first PR" if you'd like to start somewhere specific. We'll do our best to support you until your PR is merged.

Which version of Serialport would you like documentation for?

You're reading the README for the master branch of serialport. You probably want to be looking at the README of our latest release. See our change log for what's new and our upgrade guide for a walk through on what to look out for between major versions.

[email protected] docs are here this is the latest 5.x releases.
[email protected] docs are here it is the latest 4.x releases.
[email protected] docs are here it is the latest 3.x releases.
[email protected] docs are here it was the last 2.x release
[email protected] docs are here it was the last 1.x release

Imagine a world where you can write JavaScript to control blenders, lights, security systems, or even robots. Yes, I said robots. That world is here and now with node serialport. It provides a very simple interface to the low level serial port code necessary to program Arduino chipsets, X10 wireless communications, or even the rising Z-Wave and Zigbee standards. The physical world is your oyster with this goodie. For a full break down of why we made this, please read NodeBots - The Rise of JS Robotics.

For getting started with node-serialport, we recommend you begin with the following articles:

Johnny-Five - The Johnny-Five Robotics and IoT platform's 6 line "Hello World" (awesome).
Arduino Node Security Sensor Hacking - A great all around "how do I use this" article.
NodeBots - The Rise of JS Robotics - A survey article of why one would want to program robots in JS and how this all started.

Platform Support
Installation
Installation Special Cases
License
Usage
SerialPort ⏏
- new SerialPort(path, [options], [openCallback])
- instance
  - .open([callback])
  - .update([options], [callback])
  - .write(data, [encoding], [callback]) ⇒ boolean
  - .read([size]) ⇒ string | Buffer | null
  - .close(callback)
  - .set([options], [callback])
  - .get([callback])
  - .flush([callback])
  - .drain([callback])
  - .pause() ⇒
  - .resume() ⇒
  - Event: "error"
  - Event: "open"
  - Event: "data"
  - Event: "disconnect"
  - Event: "close"
- static
  - .Binding : Binding
  - .parsers : object
  - .list(callback) : function
- inner
  - ~Binding : Class
  - ~readCallback : function
  - ~errorCallback : function
  - ~modemBitsCallback : function
  - ~openOptions : Object
  - ~listCallback : function
Command Line Tools
- Serial Port List
- Serial Port Terminal

Platform Support

serialport supports and tests against the following platforms, architectures and node versions.

Platform / Arch	Node v0.10.x	Node v0.12.x	Node v4.x	Node v6.x	Node v7.x
Linux / ia32	☑	☑	☑	☑	☑
Linux / x64	☑	☑	☑	☑	☑
Linux / ARM v6¹	☐	☐	☐	☐	☐
Linux / ARM v7¹	☐	☐	☐	☐	☐
Linux / ARM v8¹	☐	☐	☐	☐	☐
Linux / MIPSel¹	☐	☐	☐	☐	☐
Linux / PPC64¹	☐	☐	☐	☐	☐
Windows² / x86	☑	☑	☑	☑	☑
Windows² / x64	☑	☑	☑	☑	☑
OSX³ / x64	☑	☑	☑	☑	☑

¹ ARM, MIPSel and PPC64¹ platforms are known to work but are not currently part of our test or build matrix. #846 ARM v4 and v5 was dropped from NodeJS after Node v0.10.

² Windows 7, 8, 10, and 10 IoT are supported but only Windows Server 2012 R2 is tested by our CI.

³ OSX 10.4 Tiger and above are supported but only 10.9.5 Mavericks with Xcode 6.1 is tested in our CI.

Installation Instructions

For most "standard" use cases (node v4.x on mac, linux, windows on a x86 or x64 processor), node-serialport will install nice and easy with a standard;

npm install serialport

Installation Special Cases

We are using node-pre-gyp to compile and post binaries of the library for most common use cases (linux, mac, windows on standard processor platforms). If you are on a special case, node-serialport will work, but it will compile the binary when you install.

This assumes you have everything on your system necessary to compile ANY native module for Node.js. This may not be the case, though, so please ensure the following are true for your system before filing an issue about "Does not install". For all operating systems, please ensure you have Python 2.x installed AND not 3.0, node-gyp (what we use to compile) requires Python 2.x.

Alpine Linux

Alpine is a (very) small distro, but it uses the musl standard library instead of glibc (that most other Linux distros use), so it requires compilation. It's commonly used with Docker. We have been confirmed to work with apline-node.

# If you don't have node/npm already, add that first
sudo apk add --no-cache nodejs

# Add the necessary build and runtime dependencies
sudo apk add --no-cache make gcc g++ python linux-headers udev

# Then we can install serialport, forcing it to compile
npm install serialport --build-from-source

# If you're installing as root you'll need to use

Electron

Electron is a framework for creating cross-platform desktop applications. Electron comes with it's own version of the Node.js runtime.

If you require serialport as a dependency for an Electron project you need to compile it for the version of Electron you're using in your project.

When you first install serialport it will compile against the version of Node.js on your machine, not against the Node.js runtime bundled with Electron.

To recompile serialport (or any native Node.js module) for Electron you can use electron-rebuild.

npm install --save-dev electron-rebuild
Delete existing Node.js binding node_modules/serialport/build/Release/serialport.node
Run electron-rebuild
For Windows .\node_modules\.bin\electron-rebuild.cmd
For Linux and macOS ./node_modules/.bin/electron-rebuild

For more information on electron-rebuild visit the official README.

Illegal Instruction

The pre-compiled binaries assume a fully capable chip. The Galileo 2 for example lacks a few instruction sets from the ia32 architecture. A few other platforms have similar issues. So if you get Illegal Instruction when trying to run serialport you'll need to rebuild the serialport binary by asking npm to rebuild it.

# Will ask npm to build serialport during install time
npm install serialport --build-from-source

# If you have a package that depends on serialport you can ask npm to rebuild it specifically.
npm rebuild serialport --build-from-source

# Or leave out the package name to rebuild everything.
npm rebuild --build-from-source

Mac OS X

Ensure that you have at a minimum the xCode Command Line Tools installed appropriate for your system configuration. If you recently upgraded the OS, it probably removed your installation of Command Line Tools, please verify before submitting a ticket. To compile node-serialport with Node.js 4.x+, you will need to use g++ v4.8 or higher.

Raspberry Pi Linux

Follow the instructions for setting up a Raspberry pi for use with Johnny-Five and Raspi IO. These projects use Node Serialport under the hood.

Revision	CPU	Arm Version
A, A+, B, B+	32-bit ARM1176JZF-S	ARMv6
Compute Module	32-bit ARM1176JZF-S	ARMv6
Zero	32-bit ARM1176JZF-S	ARMv6
B2	32-bit ARM Cortex-A7	ARMv7
B3	32-bit ARM Cortex-A53	ARMv8

sudo / root

If you're going to use sudo or root to install node SerialPort npm requires you to use the unsafe parameters flag. This is rarely required.

sudo npm install serialport --unsafe-perm --build-from-source

Failure to use the flag results in an error similar to the following;

root@rpi3:~# npm install -g serialport
/usr/bin/serialport-list -> /usr/lib/node_modules/serialport/bin/serialport-list.js
/usr/bin/serialport-term -> /usr/lib/node_modules/serialport/bin/serialport-terminal.js

> [email protected] install /usr/lib/node_modules/serialport
> node-pre-gyp install --fallback-to-build

gyp WARN EACCES user "root" does not have permission to access the dev dir "/root/.node-gyp/6.9.1"
gyp WARN EACCES attempting to reinstall using temporary dev dir "/usr/lib/node_modules/serialport/.node-gyp"
make: Entering directory '/usr/lib/node_modules/serialport/build'
make: *** No rule to make target '../.node-gyp/6.9.1/include/node/common.gypi', needed by 'Makefile'.  Stop.
make: Leaving directory '/usr/lib/node_modules/serialport/build'
gyp ERR! build error
gyp ERR! stack Error: `make` failed with exit code: 2

Ubuntu/Debian Linux

The best way to install any version of NodeJS is to use the NodeSource Node.js Binary Distributions. Older versions of Ubuntu install nodejs with the wrong version and binary name. If you node binary is nodejs not node or if your node version is v0.10.29 then you should follow these instructions.

The package build-essential is necessary to compile serialport. If there's a binary for your platform you won't need it. Keep rocking!

# Using Ubuntu and node 6
curl -sL https://deb.nodesource.com/setup_7.x | sudo -E bash -
sudo apt-get install -y nodejs

# Using Debian and node 6, as root
curl -sL https://deb.nodesource.com/setup_7.x | bash -
apt-get install -y nodejs

Windows

Windows 7, Windows 8.1, Windows 10, and Windows 10 IoT are supported. Precompiled binaries are available but if you want to build it from source you'll need to follow the node-gyp installation instructions. Once those are finished and working you'll be able to install serialport from source with;

npm install serialport --build-from-source

It's not part of node-gyp's documenation but sometimes it helps if you creates a c++ project in visual studio so it will install necessary comonents that aren't installed during the two hours of setup you just sat through. This will solve some instances of Failed to locate: "CL.exe".

License

SerialPort is MIT licensed and all it's dependencies are MIT or BSD licensed.

Usage

Opening a serial port:

var SerialPort = require('serialport');
var port = new SerialPort('/dev/tty-usbserial1', {
  baudRate: 57600
});

When opening a serial port, you can specify (in this order).

Path to Serial Port - required.
Options - optional and described below.

Opening a Port

Constructing a SerialPort object will open a port immediately. While you can read and write at any time (it will be queued into the port is open), most port functions require an open port. You can call code when a port is opened in three ways.

The open event is always emitted when the port is opened
The constructor's openCallback is passed to .open() when the autoOpen option hasn't been disabled, if you have disabled it the callback is ignored.
The .open() function takes a callback that is called after the port is opened. This can be used if you disabled the autoOpen option or have previously closed an open port.

var SerialPort = require('serialport');
var port = new SerialPort('/dev/tty-usbserial1');

port.on('open', function() {
  port.write('main screen turn on', function(err) {
    if (err) {
      return console.log('Error on write: ', err.message);
    }
    console.log('message written');
  });
});

// open errors will be emitted as an error event
port.on('error', function(err) {
  console.log('Error: ', err.message);
})

This could be moved to the constructor's callback.

var SerialPort = require('serialport');
var port = new SerialPort('/dev/tty-usbserial1', function (err) {
  if (err) {
    return console.log('Error: ', err.message);
  }
  port.write('main screen turn on', function(err) {
    if (err) {
      return console.log('Error on write: ', err.message);
    }
    console.log('message written');
  });
});

When disabling the autoOpen option you'll need to open the port on your own.

var SerialPort = require('serialport');
var port = new SerialPort('/dev/tty-usbserial1', { autoOpen: false });

port.open(function (err) {
  if (err) {
    return console.log('Error opening port: ', err.message);
  }

  // write errors will be emitted on the port since there is no callback to write
  port.write('main screen turn on');
});

// the open event will always be emitted
port.on('open', function() {
  // open logic
});

You can get updates of new data from the Serial Port as follows:

port.on('data', function (data) {
  console.log('Data: ' + data);
});

You can write to the serial port by sending a string or buffer to the write method as follows:

port.write('Hi Mom!');
port.write(new Buffer('Hi Mom!'));

Enjoy and do cool things with this code.

Debugging

We make use of the debug package and log under the serialport namespace. We log;

serialport:main for all high level main logging
serialport:binding for all low level logging

You can enable logging through environment variables. Check out the debug docs for more information.

DEBUG=serialport:main node myapp.js
DEBUG=serialport:* node myapp.js
DEBUG=* node myapp.js

Error Handling

All functions in SerialPort two conventions.

Argument Errors throw a TypeError object. You'll see these when functions are called with invalid arguments.
Runtime Errors provide Error objects to the function's callback or emit an error event if no callback is provided. You'll see these when a runtime error occurs like trying to open a bad port, or set an unsupported baud rate.

It should never be necessary to wrap a SerialPort object in a try/catch statement if you call the functions with the correct arguments.

SerialPort ⏏

Kind: Exported class
Emits: open, data, close, error, disconnect
Properties

Name	Type	Description
baudRate	`number`	The port's baudRate, use `.update` to change it. Read Only.
binding	`object`	The binding object backing the port Read Only.
isOpen	`boolean`	`true` if the port is open, `false` otherwise. Read Only.
path	`string`	The system path or name of the serial port. Read Only.

`new SerialPort(path, [options], [openCallback])`

Create a new serial port object for the path. In the case of invalid arguments or invalid options when constructing a new SerialPort it will throw an error. The port will open automatically by default which is the equivalent of calling port.open(openCallback) in the next tick. This can be disabled by setting the option autoOpen to false.

Throws:

TypeError When given invalid arguments a TypeError will be thrown.

Param	Type	Description
path	`string`	The system path of the serial port to open. For example, `/dev/tty.XXX` on Mac/Linux or `COM1` on Windows.
[options]	`openOptions`	Port configuration options
[openCallback]	`errorCallback`	Called when a connection has been opened. If this is not provided and an error occurs, it will be emitted on the ports `error` event. The callback will NOT be called if autoOpen is set to false in the openOptions as the open will not be performed.

`serialPort.open([callback])`

Opens a connection to the given serial port.

Kind: instance method of SerialPort
Emits: open

Param	Type	Description
[callback]	`errorCallback`	Called when a connection has been opened. If this is not provided and an error occurs, it will be emitted on the ports `error` event.

`serialPort.update([options], [callback])`

Changes the baud rate for an open port. Throws if you provide a bad argument. Emits an error or calls the callback if the baud rate isn't supported.

Kind: instance method of SerialPort

Param	Type	Description
[options]	`object`	Only `baudRate` is currently supported
[options.baudRate]	`number`	The baud rate of the port to be opened. This should match one of commonly available baud rates, such as 110, 300, 1200, 2400, 4800, 9600, 14400, 19200, 38400, 57600, 115200. There is no guarantee, that the device connected to the serial port will support the requested baud rate, even if the port itself supports that baud rate.
[callback]	`errorCallback`	Called once the port's baud rate has been changed. If `.update` is called without an callback and there is an error, an error event will be emitted.

`serialPort.write(data, [encoding], [callback])` ⇒ `boolean`

Writes data to the given serial port. Buffers written data if the port is not open.

The write operation is non-blocking. When it returns, data may still have not actually been written to the serial port. See drain().

Some devices like the Arduino reset when you open a connection to them. In these cases if you immediately write to the device they wont be ready to receive the data. This is often worked around by having the Arduino send a "ready" byte that your node program waits for before writing. You can also often get away with waiting around 400ms.

Even though serialport is a stream, when writing it can accept arrays of bytes in addition to strings and buffers. This extra functionality is pretty sweet.

Kind: instance method of SerialPort
Returns: boolean - false if the stream wishes for the calling code to wait for the 'drain' event to be emitted before continuing to write additional data; otherwise true.

Param	Type	Description
data	`string` \| `array` \| `buffer`	Accepts a `Buffer` object, or a type that is accepted by the `Buffer` constructor (ex. an array of bytes or a string).
[encoding]	`string`	The encoding, if chunk is a String. Defaults to `'utf8'`. Also accepts `'ascii'`, `'base64'`, `'binary'`, `'hex'` See Buffers and Character Encodings for all available options.
[callback]	`function`	Called once the write operation finishes. Data may not yet be flushed to the underlying port, no arguments.

`serialPort.read([size])` ⇒ `string` | `Buffer` | `null`

Request a number of bytes from the SerialPort. The read() method pulls some data out of the internal buffer and returns it. If no data available to be read, null is returned. By default, the data will be returned as a Buffer object unless an encoding has been specified using the .setEncoding() method.

Kind: instance method of SerialPort
Returns: string | Buffer | null - The data from internal buffers

Param	Type	Description
[size]	`number`	size specify how many bytes of data to return if available.

`serialPort.close(callback)`

Closes an open connection

Kind: instance method of SerialPort
Emits: close

Param	Type	Description
callback	`errorCallback`	Called once a connection is closed.

`serialPort.set([options], [callback])`

Set control flags on an open port. Uses SetCommMask for windows and ioctl for mac and linux.

Kind: instance method of SerialPort

Param	Type	Default	Description
[options]	`object`		All options are operating system default when the port is opened. Every flag is set on each call to the provided or default values. If options isn't provided default options will be used.
[options.brk]	`Boolean`	`false`
[options.cts]	`Boolean`	`false`
[options.dsr]	`Boolean`	`false`
[options.dtr]	`Boolean`	`true`
[options.rts]	`Boolean`	`true`
[callback]	`errorCallback`		Called once the port's flags have been set.

`serialPort.get([callback])`

Returns the control flags (CTS, DSR, DCD) on the open port. Uses GetCommModemStatus for windows and ioctl for mac and linux.

Kind: instance method of SerialPort

Param	Type	Description
[callback]	`modemBitsCallback`	Called once the modem bits have been retrieved.

`serialPort.flush([callback])`

Flush discards data received but not read and written but not transmitted. For more technical details see tcflush(fd, TCIFLUSH) for Mac/Linux and FlushFileBuffers for Windows.

Kind: instance method of SerialPort

Param	Type	Description
[callback]	`errorCallback`	Called once the flush operation finishes.

`serialPort.drain([callback])`

Waits until all output data has been transmitted to the serial port. See tcdrain() or FlushFileBuffers() for more information.

Kind: instance method of SerialPort

Param	Type	Description
[callback]	`errorCallback`	Called once the drain operation returns.

Example
Writes data and waits until it has finish transmitting to the target serial port before calling the callback.

function writeAndDrain (data, callback) {
  sp.write(data, function () {
    sp.drain(callback);
  });
}

`serialPort.pause()` ⇒

The pause() method will cause a stream in flowing mode to stop emitting 'data' events, switching out of flowing mode. Any data that becomes available will remain in the internal buffer.

Kind: instance method of SerialPort
Returns: this
See: module:serialport#resume

`serialPort.resume()` ⇒

The resume() method causes an explicitly paused Readable stream to resume emitting 'data' events, switching the stream into flowing mode.

Kind: instance method of SerialPort
Returns: this
See: module:serialport#pause

`Event: "error"`

The error event's callback is called with an error object whenever there is an error.

Kind: event emitted by SerialPort

`Event: "open"`

The open event's callback is called with no arguments when the port is opened and ready for writing. This happens if you have the constructor open immediately (which opens in the next tick) or if you open the port manually with open(). See Useage/Opening a Port for more information.

Kind: event emitted by SerialPort

`Event: "data"`

The data event puts the port in flowing mode. data will be emitted as soon as it's received. Data will be a Buffer object with a varying amount of data in it. The readLine parser converts the data into string lines. See the parsers section for more information on parsers and the NodeJS stream documentation for more information on the data event.

Kind: event emitted by SerialPort

`Event: "disconnect"`

The disconnect event's callback is called with an error object. This will always happen before a close event if a disconnection is detected.

Kind: event emitted by SerialPort

`Event: "close"`

The close event's callback is called with no arguments when the port is closed. In the event of an error, an error event will be triggered

Kind: event emitted by SerialPort

`SerialPort.Binding` : `Binding`

The Binding is how node SerialPort talks to the underlying system. By default we auto detect windows, Linux and OSX and load the appropriate module for your system. You can assign SerialPort.Binding to any backend you like. You can find more by searching on npm.

You can also avoid auto loading the default backends by requiring SerialPort with

var SerialPort = require('serialport/lib/serialport');
SerialPort.Binding = MyBindingClass;

Kind: static property of SerialPort

`SerialPort.parsers` : `object`

The default Parsers are Transform streams that will parse data in a variety of ways and can be used to process incoming data.

To use any of the parsers you need to create them and then pipe the serialport to the parser. Be sure not to write to the parser but to the SerialPort object.

Kind: static property of SerialPort
Properties

Name	Type	Description
ByteLength	`Class`	is a transform stream that emits data as a buffer after a specific number of bytes are received.
Delimiter	`Class`	is a transform stream that emits data each time a byte sequence is received.
Readline	`Class`	is a transform stream that emits data after a newline delimiter is received.

Example

var SerialPort = require('serialport');
var Readline = SerialPort.parsers.Readline;
var port = new SerialPort('/dev/tty-usbserial1');
var parser = new Readline();
port.pipe(parser);
parser.on('data', console.log);
port.write('ROBOT PLEASE RESPOND\n');

// creating the parser and piping can be shortened to
var parser = port.pipe(new Readline());

To use the byte length parser, you must provide the length of the number of bytes:

var SerialPort = require('serialport');
var ByteLength = SerialPort.parsers.ByteLength
var port = new SerialPort('/dev/tty-usbserial1');
var parser = port.pipe(new ByteLength({length: 8}));
parser.on('data', console.log);

To use the Delimiter parser you must specify, you must provide a delimiter as a string, buffer, or an array of bytes:

var SerialPort = require('serialport');
var Delimiter = SerialPort.parsers.Delimiter;
var port = new SerialPort('/dev/tty-usbserial1');
var parser = port.pipe(new Delimiter({delimiter: new Buffer('EOL')}));
parser.on('data', console.log);

To use the Readline parser, you may provide a delimiter (defaults to '\n')

var SerialPort = require('serialport');
var Readline = SerialPort.parsers.Readline;
var port = new SerialPort('/dev/tty-usbserial1');
var parser = port.pipe(Readline({delimiter: '\r\n'}));
parser.on('data', console.log);

`SerialPort.list(callback)` : `function`

Retrieves a list of available serial ports with metadata. Only the comName is guaranteed, all the other fields will be undefined if they are unavailable. The comName is either the path or an identifier (eg COM1) used to open the serialport.

Kind: static method of SerialPort

Param	Type
callback	`listCallback`

Example

// example port information
{
  comName: '/dev/cu.usbmodem1421',
  manufacturer: 'Arduino (www.arduino.cc)',
  serialNumber: '757533138333964011C1',
  pnpId: undefined,
  locationId: '0x14200000',
  vendorId: '0x2341',
  productId: '0x0043'
}

var SerialPort = require('serialport');
SerialPort.list(function (err, ports) {
  ports.forEach(function(port) {
    console.log(port.comName);
    console.log(port.pnpId);
    console.log(port.manufacturer);
  });
});

SerialPort~Binding : `Class`

Kind: inner class of SerialPort
Properties

Name	Type	Description
isOpen	`boolean`	Required property. `true` if the port is open, `false` otherwise. Should be read only.

~Binding : Class

`new Binding(options)`

You wont ever have to use Binding objects directly they'll be used by SerialPort to access the underlying hardware. This documentation is geared towards people making bindings for different platforms.

Throws:

TypeError When given invalid arguments a TypeError will be thrown.

Param	Type	Description
options	`object`
options.disconnect	`function`	function to be called when the bindings have detected a disconnected port. This function should be called during any operation instead of that operations usual callback. The `SerialPort` class will attempt to call `close` after a disconnection and ignore any errors.

`binding.list(callback)`

Retrieves a list of available serial ports with metadata. The comName must be guaranteed and all the other fields should be undefined if they are unavailable. The comName is either the path or an identifier (eg COM1) used to open the serialport.

Kind: instance method of Binding

Param	Type
callback	`listCallback`