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Synel Protocol Communications Library
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Syndll2 is a reliable, high-performance, thread-aware implementation of the Synel Communications Protocol. It is used primarily for communicating with Synel time and attendance terminals, such as the SY700 series.


  • This library supports .Net 4.0 and higher.

  • If you are using .Net 4.5, you can optionally take advantage of asynchronous methods, using async/await patterns.

  • It has also been tested under Mono on Linux without issue.

  • It does not currently support being called via COM Interop. If you are using C++, VB6, FoxPro, or another COM-based platform, then you will not be able to use this library. You might, however, be able to interact with the SynUtil command-line wrapper via system shell calls.

A note on thread safety

  • The library is "thread-aware" in that it can be used in a multithreaded application.
    • However, an individual SynelClient class is single-threaded.
    • A connection should be created, used, and disposed in the same thread.
    • It is best to do this with a using block.
  • Multiple threads can be created, each using their own connection.
    • Simultaneous connections to the same terminal from different threads will automatically be queued so they can't interfere with each other.
    • Simultaneous connections to multiple different terminals are supported and can be run in parallel.


The best and easiest way to use Syndll2 is by adding a NuGet package reference.

PM> Install-Package Syndll2 -Pre

Note that the package is currently in prerelease status.

This will add a compiled version of Syndll2.dll to your project, and add a project reference automatically.

  • Nuget makes it very simple to update your project to the latest version of this library.
  • NuGet is available for both Visual Studio 2010 and 2012.
  • You can use the Package Manager console within Visual Studio, or you can also use a graphical interface if you prefer.
  • If you are not familiar with Nuget, please start here.
  • You can also visit the Syndll2 Nuget Feed directly.
Staying Current

As changes are made to Syndll2, you can use Nuget to keep your project updated.

PM> Update-Package Syndll2 -Pre

Again, note that the -Pre flag is required since the library is currently in prerelease status. After a stable version is published, you will no longer have to pass the -Pre flag, and this page will be updated.

Manual Installation

If you choose not to use NuGet, you can simply download the latest release from our Releases Page.

  • Unzip the package and choose either the Net40 or Net45 subdirectory, depending on which version of .Net Framework you are using.
  • Place the files somewhere in your solution directory.
  • Add a reference to the Syndll2.dll file in your project.
  • Only the Syndll2.dll file needs to be distributed with your application. The .pdb and .xml files are for debugging and Intellisense support.

Example Usage

Synchronously (.Net 4.0 or 4.5)

using (var client = SynelClient.Connect(HostAddress))
    // get a data record from the terminal
    var data = client.Terminal.GetData();

    // do something with the data here (save it to db, send it over the web, etc.)

    // acknowledge the record so the terminal will clear it

Asynchronously (requires .Net 4.5)

using (var client = await SynelClient.ConnectAsync(HostAddress))
    // get a data record from the terminal
    var data = await client.Terminal.GetDataAsync();

    // do something with the data here (save it to db, send it over the web, etc.)

    // acknowledge the record so the terminal will clear it
    await client.AcknowledgeLastRecordAsync();

Current Status / Road Map

Not all terminals or functions are currently supported. This code is safe for production, but should still be considered unstable.

Currently Implemented

  • Network connection
  • Retreiving basic data
  • Various commands for getting status
  • Setting the terminal's clock
  • Programming operations, such as uploading a terminal program.
  • Sending and retrieving fingerprint templates.
  • Server to recieve data when Polling is enabled.
  • Miscellaneous other functions.

Not yet implemented

  • Serial or modem connection.
  • Firmware Updating
  • Online Mode (Host Query)

Solution Structure

This is the main project for the library, targeting .Net 4.5.

This is a compatibility project, targeting .Net 4.0. All source files are shared as links from the main project.

This project contains unit tests to prove functionality. Most are "live tests" that require a terminal to test against.

Questions / Issues

Please contact your Synel support representative for general questions. You may also post issues to our issue tracker.

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