Tactical Software Knowledge Base

The virtual COM ports created by Tactical Software redirectors do not use IRQ’s and are generally not likely to conflict with other devices. There are two cases that might arise, however.

1. There are rare cases where a previously installed device is incorrectly recorded in the Windows registry. In some cases, third-party device drivers can install without updating the master IO port allocation entry. This can cause the software to claim an IO port that is in fact being used by another driver, causing a conflict. Generally, you simply need to go into the Device Manager and manually specify another IO port for the COM port. When you are trying other IO port possibilities,  the Device Manager does inform you of conflicts. Just keep changing the COM IO port until the dialog reports no conflicts.
    
2. There are a few third-party drivers that use the same underlying COM port redirection mechanism as Tactical Software. The driver for the HP 3100 printer is an example. A safe approach is to create virtual COM ports last and to use the Windows Device Manager to review the COM ports in use prior to deciding what you will use for the redirected COM ports.