Centronics Cable and Mixed up Signals
Posted: Mon Mar 18, 2024 12:19 am
Hi,
I bought a v3 retro printer awhile back and have just now gotten around to using it. After struggling to figure out why:
10 PRMN\ "Lmllo, orll!"
20 OO\O 10
Was being read from the port when:
10 PRINT "Hello, world!"
20 GOTO 10
Was sent. I got out a multimeter and looked at the pins on the male and female side of the centronics M/F adapter thing that came with my retro printer. It appears that Pins 4 and 5 on the male side are both wired to pin 4 on the female side and they are both wired to pin 5, as well. Is this per design? Because it seems faulty to me. These pins are listed as DATA BIT 3 and DATA BIT 4 here:
https://pinoutguide.com/ParallelPorts/i ... nout.shtml
Which would seem to cause the issues of bits being wrong as above (any time bit 3 and/or bit 3 are high, both bits 3 and 4 will go high and only when both are 0 then bits 3 and 4 will stay low.
Anyhow, is it a problem or am I confused about how it works? If it's a problem, what's my fix?
Will
I bought a v3 retro printer awhile back and have just now gotten around to using it. After struggling to figure out why:
10 PRMN\ "Lmllo, orll!"
20 OO\O 10
Was being read from the port when:
10 PRINT "Hello, world!"
20 GOTO 10
Was sent. I got out a multimeter and looked at the pins on the male and female side of the centronics M/F adapter thing that came with my retro printer. It appears that Pins 4 and 5 on the male side are both wired to pin 4 on the female side and they are both wired to pin 5, as well. Is this per design? Because it seems faulty to me. These pins are listed as DATA BIT 3 and DATA BIT 4 here:
https://pinoutguide.com/ParallelPorts/i ... nout.shtml
Which would seem to cause the issues of bits being wrong as above (any time bit 3 and/or bit 3 are high, both bits 3 and 4 will go high and only when both are 0 then bits 3 and 4 will stay low.
Anyhow, is it a problem or am I confused about how it works? If it's a problem, what's my fix?
Will