Docklight is a testing, analysis and simulation tool for serial communication protocols.

It allows you to monitor the communication between two serial devices or to test the serial communication of a single device.

Docklight is the preferred RS232 terminal / RS232 monitor / TCP or HID device tester / IoT (Internet of Things) debugging tool for numerous software and hardware engineers around the globe.

Supported interfaces and connections are RS232, RS485/RS422, TCP/UDP, Virtual COM, USB HID, Bluetooth (SPP or HID) and Named Pipes.

Docklight significantly increases productivity in a broad range of industries, including automation and control, communications, automotive, equipment manufacturers, and embedded / consumer products.

Docklight is easy to use and runs on almost any standard PC using Windows 10, Windows 8 or Windows 7 operating system.


Our Company

The company was set up in 1998 as an "Office for Multimedia and IT Solutions."

Since then our focus has shifted more and more to projects in the industrial field, so that we nowadays concentrate on this area.



Docklight RS232 Terminal / RS232 Monitor

 Simulating serial protocols – Docklight can send out user-defined sequences according to the protocol used and it can react to incoming sequences.

This makes it possible to simulate the behavior of a serial communication device, which is particularly useful for generating test conditions that are hard to reproduce with the original device (e.g. problem conditions).

Docklight PC simulates Device1 to test Device 2 behaviour.

Logging RS232 data – All serial communication data can be logged using two different file formats: use plain text format for fast logging and storing huge amounts of data. Or create a HTML file with styled text that lets you easily distinguish between incoming and outgoing data or additional information.

Detecting specific data sequences – In many test cases you will need to check for a specific sequence within the RS232 data that indicates a problem condition. Docklight manages a list of such data sequences for you and is able to perform user-defined actions after detecting a sequence, e.g. taking a snapshot of all communication data before and after the error message was received.

Monitor the communication between Device 1 and Device 2.

Test protocol or device functions.

Responding to incoming data – Docklight lets you specify user-defined answers to the different communication sequences received. This allows you to build a basic simulator for your serial device within a few minutes. It can also help you to trace a certain error by sending out a diagnostics command after receiving the error message.

Docklight will work with the COM communication ports provided by your Windows operating system. Physically, these ports will be RS232 SUB D9 interfaces in many cases. However, it is also possible to use Docklight for other communication standards such as RS485 and RS422, which have a different electrical design to RS232 but follow the RS232 communication mechanism.

Docklight has been successfully tested with a vast range of serial devices and drivers. This includes many popular USB-to-Serial converters, Bluetooth serial ports, GPS receivers, Virtual Null Modem drivers like com0com, Arduino serial ports, MicroPython/pyboard, and many other Embedded hardware devices that appear as a COM port in the Windows Device Manager.

For the software and manuals please refer to the download section. You can find Application Notes and examples for different hardware interfaces and protocols in our examples section.



Docklight Scripting

Docklight Scripting is an extended edition of Docklight RS232 Terminal / RS232 Monitor. It features an easy-to-use script language, plus a built-in editor to create and run automated test jobs.

A Docklight script allows you to execute all basic Docklight functions (sending predefined data sequences, detecting specific sequences within the incoming data stream, …) and embed them in your own test code.

Docklight Scripting is also network-enabled and supports HID or Named Pipe connections. Instead of using a serial COM port, Docklight Scripting can establish TCP connections (TCP client mode), accept a TCP connection on a local port (TCP server mode), act as a UDP peer, or access USB HID Custom Class devices. For an overview on networking applications, see our Docklight TCP/UDP and Applications, Examples sections.


Docklight Scripting gives you both, flexibility and simplicity. Within minutes you can build your own automated testing tools and create:

  • repeated test cycles(e.g. endurance testing for a motion control / drive system)
  • time-controlled test jobs(e.g. sending a diagnostics command at certain times of day)
  • automatic device configuration scripts(e.g. resetting a RS232 device to factory defaults before delivery)
  • fault analysis tools for service and maintenance tasks(e.g. running a set of diagnostics commands and performing automatic fault analysis
  • protocol testers with automatic checksum calculations(e.g. CRC – Cyclic Redundancy Codes)
  • Docklight startup scripts(e.g. automatically starting a COM port logging task at PC startup)

Docklight Scripting uses the VBScript engine, allowing you to write your tests in a simple and well-known script language. Docklight's basic functions and features are made available through a small and convenient set of script commands. The sample applications and scripts provided make getting started easy, and allow you to become productive immediately.

For the software and manuals please refer to the download section.



Docklight Pro Monitor

Docklight Pro Monitor is a Windows tool for high speed and high resolution serial communications monitoring (RS232, RS422 and RS485).

It is designed to work with the Docklight Tap Pro and Docklight Tap 485 devices. Both, Tap Pro and Tap 485 use their own high resolution hardware time base for all serial data and serial line events monitored.

Key functions include

  • Logging RS232 or RS485/422 serial data– Serial communication data can be logged and displayed in different representations: ASCII, Hexadecimal, Decimal and High-speed, flexible output formatting for both binary data and text-based
    protocols, including control characters.
  • Logging RS232 serial line states– Status Line / Handshake signals (RTS, DTR, CTS, DSR, DCR, RI) and Break State.
  • High performance and high accuracy monitoring– real-time data acquisition with milliseconds precision.
  • Real-time filtering– hide/show logged data by type or source, while the communication is running.

Docklight Pro Monitor is a free addition to Docklight Scripting. For the software and manuals please refer to the download section.


Software Sources Ltd. is Docklight's Reseller.