Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!lll-winken!uunet!mcvax!kth!sunic!slyrf!dkuug!daimi!poj
From: poj@daimi.dk (Per Olsvig Jensen)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Determining if a printer is available
Message-ID: <2137@daimi.dk>
Date: 30 Mar 89 09:46:08 GMT
References: <2165@pembina.UUCP> <7730@pyr.gatech.EDU> <42@datcon.UUCP>
Reply-To: poj@daimi.dk (Per Olsvig Jensen)
Organization: DAIMI: Computer Science Department, Aarhus University, Denmark
Lines: 42

In article <42@datcon.UUCP> sar@datcon.co.uk (Simon A Reap) writes:
>In article <7730@pyr.gatech.EDU> curci@stat.fsu.edu (Ray Curci (scri)) writes:
>>In article <2165@pembina.UUCP> lake@alberta.UUCP (Robert Lake) writes:
>>>I am trying to determine if a line printer is attached to my PC.  I am
>> :
>>                               Additionally, I believe there are also some
>>BIOS services that will give you the same information including information
>>about some of the control signals (whether your printer is on-line, out-of-paper, etc,.)
>
>But beware: as far as I can see, even hacking as assembler, there's no
>way to differentiate between an on-line paper-full printer all ready to
>roll out your pearls, and a printer that's just powered OFF :-) (sure
>saves paper that way!)  BTW, we're talking standard PC here (and a
>million and one clones) and yer actual Epson FX80.  The BIOS calls give
>identical results for the two printer states, the printer status
>registers are the same - what else can I try?
>-- 
>Enjoy,
>yerluvinunclesimon             Opinions are mine - my cat has her own ideas
>Reach me at sar@datcon.co.uk, or ...!mcvax!ukc!pyrltd!datcon!sar

On my vanilla IBM AT with DOS 3.21 with a IBM Proprinter the printer status
registers differ in the two different printer states mentioned above.
  Here's the list of different states that I've found empirically on my AT
and on a XT ( they differ only slightly on the status bit 7 (not busy)) :
  No bits set                                 means   printer not ready
  bit 4 set (selected)                        means   printer ready
  bit 4 and 7 set (selected, not busy)        means   printer ready
  bit 3 and 5 set (I/O err, out of paper)     means   printer out of paper
  bit 4 and 5 set (select, out of paper)      means   no printer at all
  bit 4, 5, 7 set (select, out of paper, not busy)    no printer at all
  bit 3 and 7 set (I/O err, not busy)         means   printer is turned off
  bit 0, 5, 7 set (timeout, out of paper, not busy)   printer is printing

  BTW, is also seems to vary between the two machine when the last status
(printer is printing) is set.

I'll be happy to hear about other combinations of printer status bits.

-Regards
 Per Olsvig Jensen
 DAIMI - Department of Computer Science, Aarhus University, Denmark