When I use Docklight with my USB-to-RS232 (RS485) device or other USB connectivity, Docklight sporadically reports “General I/O error on COMx / General error while accessing the communication port” and resets/reopens the connection. This does not happen with Docklight V2.2.

When I use Docklight with my USB-to-RS232 (RS485) device or other USB connectivity, Docklight sporadically reports “General I/O error on COMx / General error while accessing the communication port” and resets/reopens the connection. This does not happen with Docklight V2.2.

Applies to: Docklight / Docklight Scripting V2.3, Article ID: dl_prb055

In Docklight V2.3 versions the reaction to a Windows “WaitCommEvent” error was changed. V2.3 detects such error situations and attempts to close/reopen the affected COM port. This hotplug / reconnect / auto-recovery feature is also implemented for HID, TAP and TAPpro connections.

We have received isolated reports of the above error message appearing even in standard operation with certain COM drivers, specifically Eltima’s virtual COM drivers (reproduced on our side) and Silabs CP210x USB chipsets (not reproducible, tested on two different Windows 10 systems, stress test with approx. 0.5GB of full-duplex data transfer at 1MBit/s ok, Driver versions 10.1.8.2466 and 10.1.10.103).

As an immediate workaround:
– Please use the Docklight V2.2 versions as available from our software archive or via the direct download links below, where the error is ignored. All V2.3 project and script files are fully compatible and can be used with the V2.2 versions.

We are currently investigating this issue further and consider an extra ‘Expert Option’ to address the observed device driver behavior. We are therefore very interested in any additional feedback about any similar problem you have experienced with a specific kind of COM port equipment or software.

Download Docklight V2.2.8

Download Docklight Scripting V2.2.8

e-mail to Docklight Technical Support