Hello,
Seems I've run into a slight issue that I'm also curious about.
My ImageWriter DIPs are set to the defaults (11101011 0010) and so are my Super Serial DIPS (terminal mode, 0001011 1001100). However, in AppleWriter 2.1 when printing with the defacto 9600,8,N,1 setting, nothing is printed. It's only when I set DIP 5 on the printer to zero (ignores 8th data bit) that it prints correctly.
Not that this is a serious issue, I'm just curious if this is the correct setup and why it's happening. I'd like to learn about parity and whatnot :)
?
I presume that the terminal block on the Super Serial Card is set correctly to "Terminal" and not "modem"?
Also, I presume that you have a printer cable and not a (very similar looking from the outside) IIGS / MAC modem cable?
Also,I am not certain your switch settings are at the defaults:
The Imagewriter defaults are as follows:
Imagewriter.jpg
And the Super Serial Card's switches are meant to be as follows:
imagewriter SSC.jpg
EDIT: it has occurred to me that you're using an Imagewriter I, not a II. I'm not that familiar with the older Imagewriter, but you may be on to something since the Apple II ASCII "standard" is to use a 7-bit system, rather than the 8-bit system that's standard everywhere else. So, setting switch 1-5 to 7-bit mode would solve that problem as you discovered:
imagewriter 1.jpg
RS-232 parity bits are based on the number of 0 bits in a character. If a character is transmitted in 8 bits instead of 7, there will be an additional 0, which means that the parity is reversed. This sometimes surprises users.
Aha! I never knew that. I haven't tried 7 bits with Applewriter 2.1 but I did try PR#1 at the basic prompt and the computer softlocks. I didn't assume this was supossed to happen. As for the switches, they're set to the defaults (besides the 7 bits), the jumper is set to terminal mode, and the serial cable has worked with the printer in the past, but as for appearance I don't know if it's null modem or straight through.
I wonder though, why is 8 bits the default if Apple ascii is 7 bits? Compatibility? 8 bits does work on my 486 DOS machine.
Based on your original message - you have the Super Serial Card set to 7 bit mode (bank 2, switch 1 OFF) so the printer should match.
My SSC bank 2 switch 1 is set to on (0001011 1001100), right?