Parallel Printer Auto Switch

Categories: > Parallel Electronics
This product allows multiple CPUs to share one parallel printer (or other parallel device) without the need for manual selection or sharing.

Temporarily Unavailable Online

This product may have been transitioned to a newer version, or it may not yet be available online for other reasons.

For status, pricing, and alternative solutions, please contact our Sales department!

The 3220-series Auto Parallel Switches are electronic data switches which support Bi-Directional Centronics Parallel data transmission, including IEEE-1284 "nibble" mode.

This product allows multiple CPUs to share one parallel printer (or other parallel device) without the need for manual selection or sharing.

Automatic input selection is on a first-come, first-served basis. When one user is finished printing, the auto-switch waits for a period of time (adjustable from 5-60 seconds), then reverts to polling all input ports for activity.

Special Note for Really Really Really Old Computers:

Most Bi-Tronics (BiDirectional) auto switches support the two drivers HP LaserJet 5 provides, "Explorer" (under DOS) and "Status Window" (under Windows 3.1), but are not suitable to work in these two drivers.

In the old version of Explorer (provided with HP LaserJet 4), the user has to request the printer status manually. In the HP 5 version of Explorer and in Status Window, however, the CPU requests the printer status automatically whenever it is free; in case any odd situation occurs in the printer, it is shown on the monitor right away.

If the 3220 Parallel Auto-Switch unit is in use with the new version of Explorer or Status Window environment, two unexpected incidents will occur:

When one PC is requesting the printer status, the printer is occupied for about one second. In the meantime, if another PC attempts to request the printer status, its request will not be accepted. Because this request is automatically performed by the CPU, it will often happen that while a user is using applications other than Explorer or Status Window, the user will surprisingly get a message on the monitor saying that the printer is offline or that the cable is disconnected.

When one PC is sending its print job, it occupies the printer for a time. The other PC then gets a message on the monitor saying that the printer is off, or offline, or that the cable is disconnected.

The 3220 does support Explorer and Status Window, but the above two situations are unavoidable when either of these are active. Therefore, to avoid being disturbed by these messages, we suggest you use the switch in applications other than the newest versions of Explorer and Status Window.

To disable Explorer, comment out the STAT command in the autoexec.bat file.

To disable Status Window, close the Status Window application when in Windows.