It 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.

This program will work with the COM communication ports provided by your operating system. Physically, these ports will be RS232 SUB D9 interfaces in most cases. However, it is also possible to use this program for other communication standards, such as RS422 and RS485, which have a different electrical design to RS232 but follow the RS232 communication mechanism. Docklight has also been successfully tested with various USB-to-RS232 converters.