[conspire] HP LaserJet4 - CUPS lists printer twice

[Rick Moen]

Quoting Darlene Wallach (freepalestin at dslextreme.com):

> The printer I got from Bruce is a HP LaserJet 4M Plus

OK, there you go.  A LaserJet 4M Plus is not the same as a LaserJet 4.
In your earlier post, you opened your explanation by saying it's a
LaserJet 4 -- as does your Subject header, still, in fact.  (So, that
part was incorrect, and led me down the wrong path.)

Anyhow, your original question was:  "Why is it [the printer] listed
twice?"  Answer:  It's not.  Those were two distinct configurations of
filter ("driver") and port selection that CUPS suggested as, in its
view, suitable choices for the "Available" (i.e., probed) printer.

So, I hear you asking, if they're distinct, what's the difference
between them?  Answer:  Not 100% sure, but the second of the two says
"HPLIP", which seems to designate the OpenPrinting-recommended driver
package.

If you were to install them both, and then look at the resulting PPD
files under your /etc/cups/ppd/ directory, you might find that the
second used a hplip driver, and the first some more ancient PCL driver.