I got my old Epson Apex 80 printer going. I can print with no issues from all three Quadboard cards. There is another passage in that Quadboard manual I mentioned previously that states that their parallel port is identical to IBM's except for three "seldom used" lines that were not brought out. They are AUTO FD XT, ERROR, and SLCT IN. None of these cards pass Checkit diagnostics, but they all print to this old dot matrix printer flawlessly. I wouldn't think a Laserjet 4L would be too modern. That's a pretty old printer. I wonder though, if something else isn't preventing it printing.
The parallel Covox sound card is very cool. Where did you find the info to make one?
Many thanks for your effort, now i can be sure that i have made the cable correctly (tested several times with multimeter) and now i also know it's not even meant to pass the Checkit test.
I have the software for my Quadboard with QUADTEST.BAS which has option to test printer, If that Laserjet 4L is connected it just says "Printer port ERROR" straight. If it's not, it doesn't say anything and i can run the test but it just tries to print a set of characters to printer port over and over again, when i looked into the Basic source code.
OK I installed another I/O card as LPT2 and tried to print to it. It doesn't print anything from single DOS command, Checkit or any program but when i press shift-printscreen the data light on the printer blinks once like it's receiving data and when i tap printscreen few more times or repeat the command many times it starts to print..Data light stays on after that though probably because there is still something on queue, dunno but it's not normal.
It really looks to me like the printer has some kind of buffer which has to be filled up until it prints out it all, must be just some compatibility issue, slightly different protocol or something... At least it did something with that another card and i'm sure the printer is working.
After all that i connected it to the Quadboard again. Same thing, it doesn't even blink the light.
I think i give up on the Laserjet, i wasn't going to use it on that computer anyway, just wanted to test the port. I just hope the card is not broken..
I think the most reliable way to test the port is to build a tester with resistor and LED for every line and write a program for it to set every line on and off one at a time.. I have RS232 tester and it has been useful few times.
Hmm.. could it be those "missing" control lines be the reason the Laserjet or even the Parallel Laplink cable is not working like it should? At least the Laplink cable uses pins 13 "Select In" and 15 "Error"
http://en.wikipedia.org/wiki/LapLink_cable.
Tester would maybe tell that too.. I'm going to build one or order el cheapo from china, probably cheaper to order it than build it with parts, but when i order it i miss the fun part soldering and assembling it :]
Just when i was writing this message, my PCI-E RS232 adapter arrived from China to my mailbox and now i'm going to test file transfer and all that! I don't need to sleep..! =)
That "Covox Speech Thing"-clone:
Schematics:
http://www.epanorama.net/circuits/dacs.html
The thing in action:
http://www.youtube.com/watch?v=1-QHlF6cPKk
http://en.wikipedia.org/wiki/Covox_Speech_Thing
Many demos and games from that era support that card which made it awesome back then and it was almost free to build, just a few resistors, some connectors and that's it. There is a more sophisticated version in that epanorama link which uses a chip but also needs 5V external power, i haven't tried that but i don't think it has very much difference in sound quality than the basic version.
