Two same model USB Printer

Michael R Sweet msweet at
Thu Sep 18 22:11:30 PDT 2008

keens312 wrote:
> Hi Michael,
> I am thinking a case like that:
> I have two USB printer connected to OSX 10.5.
> The printers are the same model (using the same USB vendorID, productID).
> Now I add both of them into printer center with CUPS driver.
> Print a job to each of the printer.
> What will happen, will CUPS distinguish the two and send the job accurately?
> My last test shows that jobs are sent to the first USB printer.

If you follow the USB and 1284 specs, your devices will report a
unique serial number which will allow the system to distinguish
between your printers.

If not, Mac OS X 10.5.x will assign a location ID based on the port
you connected the printer to so it can talk to the desired printer,
however if you move the connector the printers stop working.

On older releases of Mac OS X, the jobs will all go to the first
printer on the bus.

Michael R Sweet                        Senior Printing System Engineer

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