jeboritz@watdragon.waterloo.edu (J. Efrim Boritz) (09/21/88)
Is it possible to use the parallel printer port for input? From reading
the Tech. Ref. Manual, I get the idea that having an external device drive
the data pins is a no-no. Is this the case?
If possible, I want to write a program to receive what the printer is getting
(from another computer over a network) to track a problem we are having.
I would appreciate any pointers (or even code?!?) from anyone with some
knowledge in this area.
Respond to
jeboritz@dragon.waterloo.edu
or watmath!watdragon!jeboritz
or nick@wataco.bitnet
Thanks in advance, Nick.tsp@ncsc1.AT&T.NCSC (Tom Poindexter x8862) (09/22/88)
I have seen advertised a software-based network package that runs through
parallel ports. It's LanLink 5X from The Software Link; I think they use
some sort of special cable to get the proper signal lines routed. This
would certainly imply both input & ouput through the port.
Also, check out the last few Byte issues; Steve Ciracia articles on 8051
development make use of an PC's parallel port as I/O to the controller. He
shows a few hardware modifications (trace cuts, et.al.) that are needed
to make an IBM parallel port work, and mentions that many clone parallel
port boards should work bi-directionally as is.
If you are really just interested in seeing what is sent to a printer over a
network, I think you could just use any of the public domain printer
spoolers that use a disk file; spool to disk, then hex dump the file.
With a little more work, just trap INT 17H (I think) on the PC that has
the printer attached. That's the standard BIOS interrupt to the printer
driver. Any spooler or network redirector takes over this interrupt to
provide its' own services.
-tp
--
Tom Poindexter {where ever}!att!ncsc5!tsp sl@van-bc.UUCP (pri=-10 Stuart Lynne) (09/23/88)
In article <8579@watdragon.waterloo.edu> jeboritz@watdragon.waterloo.edu (J. Efrim Boritz) writes: > >Is it possible to use the parallel printer port for input? From reading >the Tech. Ref. Manual, I get the idea that having an external device drive >the data pins is a no-no. Is this the case? > >If possible, I want to write a program to receive what the printer is getting >(from another computer over a network) to track a problem we are having. >I would appreciate any pointers (or even code?!?) from anyone with some >knowledge in this area. > You can't do what you want to do. But you can read some data via the parallel port. Basically there are about 4 status bits that can be read, with an appropriate cable you can swap 4 of the data bits and the 4 status bits. Then each side can send nibbles (4 bits) of data which can be received at the far end. This is how some of the file transfer products work. It's actually quite fast, basically dependant on how fast each end can raise and lower the handshake lines. -- Stuart.Lynne@wimsey.bc.ca {ubc-cs,uunet}!van-bc!sl Vancouver,BC,604-937-7532
dts@cloud9.UUCP (Daniel Senie) (09/25/88)
[Question about using the Parallel port for input] The parallel port on the PS/2 is bidirectional, and so can be used for input as well as output. The ports on all other IBM PC based machines (including every clone I have seen specs. for) are set up for output only. The only "input" lines are status things like paper out. -- Daniel Senie UUCP: harvard!ulowell!cloud9!dts Stratus Computer, Inc. ARPA: anvil!cloud9!dts@harvard.harvard.edu 55 Fairbanks Blvd. CSRV: 74176,1347 Marlboro, MA 01752 TEL.: 508 - 460 - 2686
u-dmfloy%sunset.utah.edu@utah-cs.UUCP (Daniel M Floyd) (09/25/88)
I wrote a lengthy reply to the original requestor including enough technical detail to get the job done (I think); however, he writes back that he solved the problem without the parallel input port. He continued that he might do it anyway to satisfy curiosity. I believe mine (Leading Edge (tm)) does do both input and output on the parallel port. At least that's what the block diagram and the technical reference seem to indicate. I havn't tried though. I believe that other machines may be equally equiped although the documents may not write about it. After all, the intention was for output. Clearly, an input on the printer port is hacking outside of normal use. Dan Floyd 8<D=
corbin@pinocchio.Encore.COM (Steve Corbin) (09/26/88)
> The ports on all other IBM PC based machines > (including every clone I have seen specs. for) are set up for output > only. The only "input" lines are status things like paper out. Hmmm. My Multi I/O clone card has a bidirectional parallel printer port. I have no idea who makes the card. The only identifying marks on the manual are YL-16. No manufacturer name or country of origin.