alen@crash.cts.com (Alen Shapiro) (04/11/90)
I have been trying for the last 3 weeks to diagnose problems connecting MAC<->SPARCstation1 via RS232 at 19200baud. POINTS TO NOTE uucp, ZMODEM and XMODEM do NOT use XON/XOFF and so HW flow control seems essential. Even on a modem at 2400 baud I have noticed character loss down RS232 uucp (modem was error correcting MNP). OBSERVATIONS about hardware control signals There seems to be no way for the SUN to tell the mac to stop sending (sun does not generate active HW flow-control signals) When MAC is busy it drops DTR (at least Microphone II does) OBSERVED PROBLEMS Just about any console activity on the SPARC conflicts with incomming RS232 activity and characters are lost Some SCSI disk activity has the same effect CONCLUSIONS Streaming protocols like ZMODEM are probably not going to be able to transfer significant quantities of data at high speeds from mac to SPARC XMODEM may work but a patch is needed to stop Ring-Buffer overflow messages on the console from causing further character loss (the adb patch from sun follows; as root % adb -w /vmunix - splsoftclock+c?x # verify 2680 stored here else DO NOT PROCEED .?w 1080 $q then reboot) QUESTIONS Has anyone solved this problem, Is there a better NULL-modem cable connect than a symetrical 2->3 4&5->8 6->20 7->7 between SPARC&Mac. Who do I complain to for the lack of RS232 SPARC capability? (0.5 :-)) email me if you like - I'll post a summary. --alen the Lisa slayer (trying to turn a SPARC into a flame) ...alen%shappy.uucp@crash.cts.com (a mac+ uucp host - what a concept!!) ...alen@crash.cts.com