userUSSR@mts.ucs.UAlberta.CA (Chris Thierman) (09/28/90)
In article <9701@ubc-cs.UUCP>, rlin@cs.ubc.ca (Robert Lin) writes: >I noticed the new serial ports on NeXTs are RS-423's, not RS-422's. > >Does anyone know if the old bugbears of serial flow control have been >solved? I.e. do we get hardware flow control now, and does software >flow control now work at bps >= 19,200? > >-Robert Lin <rlin@cs.ubc.ca> Interesting that I should run into this question. I've been just trying to get an HP laser printer working from the NeXT using some HPLaser printer filters. I've been sending to it at 9600 baud and it almost works fine except I keep getting an error code of 40 on the printer after a couple of sheets have passed through. After sticking a data analyser on the line I noticed that when the printer sent out a DC3 (CONTROL-S) that the next ignored it, the printer then waited for ?four character times and then again sent out another DC3, followed by another 4 character times then DC3,DC3,DC3,DC3,DC3 ... about 12 times. At which point it gave up and printed a 40 on the display and hung. Needless to say the next ignored these messages until it decided it was ready to take notice. At which time it was too late. My question is can I get around this and how? Does this mean all the flow control is handled at the software level wrather then hardware. And if so how come at such a low priority??? =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= Chris Thierman E-Mail: thierman@namao.ucs.UAlberta.CA University Computing Systems Phone: (403) 492-2462 352 General Services Building University Of Alberta Edmonton, Alberta Canada T6G 2H1