how can i write out to a serial device under Linux and wait until that device is ready to receive more data? device in question is a Panasonic RK-P400C and under pyserial listening to flush, DSR and CD neither work, several commands are overwritten and skipped
top is using arbitrary 3 second delays between each circle, bottom is several attempts trying to let hardware flow control tell me when i can send new commands or not which doesn't work because the commands clobber each other and several circles are skipped
i'd like to think printer interfaces in the 80s didn't have random arbitrary waits programmed into them to avoid this command clobbering and that hardware flow control actually works
from all i can tell debugging pyserial.dsr and hooking my scope up to dtr on the typewriter, the signal is being driven as i assume it should, but still messages are being clobbered no matter what which makes this plotter impossible to use as a printer
i'm at my wit's end
this was resolved thanks again to Paul Rickards! turns out using DTR wired to host's DSR as null modem serial cables usually are doesn't work with my setup, however rewiring it to CTS instead works as intended enabling hardware flow control on the host. https://twitter.com/paulrickards/status/1394123341775126530
i know plenty of retro computer people follow me so please if you don't know the answer retweet so it can reach someone who might