What Is "Bi-Directional" for Printers?
By John Papiewski
Your business office printer has its own sophisticated computer dedicated to managing the device's operation and monitoring its status. Regardless of whether your PC connects to the printer over a network or through a USB cable, the communication between the computer and printer is bi-directional: each "talks" to the other. The PC sends the printer documents and the printer sends the computer status messages. Though this technology generally works well, it can also cause problems.
When you click the "Print" button in an application program, the computer sends document data to a program in Windows called the "spooler." This keeps the data in a temporary holding area until the printer is ready to receive it. The spooler feeds the printer a few pages at a time and removes the print job from the queue when the printer receives the last page. Document data includes the file name, the text, fonts and other formatting information, and any graphics in the file. This data flows from the computer to the printer.
Printer Status Data
The printer sends data to the PC, signaling various kinds of status information, such as the completion of a print job or problems including paper jams, empty paper trays and low laser toner levels. The "driver," a program which runs on your computer and performs print management tasks, may respond to these messages by showing alerts on your display. When the printer resides in another room, this helps you address problems about which you would otherwise be unaware.
Effect on Performance
Many hundreds of drivers exist, each one tailored to a specific make and model printer. Sometimes, a particular version of Windows does not work perfectly with a driver, resulting in slow performance and erratic print behavior. Also, status messages from the printer driver may cause unintended problems, including popup alerts that interrupt your work. The status information, while handy, is optional. In many instances, Microsoft and printer manufacturers recommend to disable bi-directional printing if it causes problems.
Disabling Bi-Directional Printing
By turning bi-directional printing off, the printer receives documents from the PC, but the driver no longer acts on messages from the printer. Open the "Printers" folder, right-click the icon representing the bi-directional printer, and then select "Properties" from the popup menu that appears. Click the "Ports" tab, then click the check box marked "Enable bidirectional support" to clear it. Click the "OK" button to disable the bi-directional print feature.
Chicago native John Papiewski has a physics degree and has been writing since 1991. He has contributed to "Foresight Update," a nanotechnology newsletter from the Foresight Institute. He also contributed to the book, "Nanotechnology: Molecular Speculations on Global Abundance."