ecs40hw021@vega.ucdavis.edu (Steve Bancroft) (02/05/89)
I have owned a 1670 modem since the first few months of their availability,
and since have noticed a certain bug and have questions about it:
(*) If a 1571 drive (or drives) is/are hooked up to the serial port while
I am using the 1670, at least one of them must be turned on before
the modem will accept dialing commands, or recognize carriers.
Has this bug affected anyone else? If so, is there an available chip,
or something I can buy or do to correct this problem?
Thanks!
Steven Bancroft --- "I'm O.K., You're 8k."
ecs40hw021@vega.ucdavis.edufred@cbmvax.UUCP (Fred Bowen) (02/06/89)
In article <3611@ucdavis.ucdavis.edu> ecs40hw021@vega.ucdavis.edu (Steve Bancroft) writes: >(*) If a 1571 drive (or drives) is/are hooked up to the serial port while > I am using the 1670, at least one of them must be turned on before > the modem will accept dialing commands, or recognize carriers. > >Has this bug affected anyone else? If so, is there an available chip, >or something I can buy or do to correct this problem? You have a C128, on which the serial port external reset line is shared with the user port reset line. If there is a drive on the serial bus that is not turned on, it can hold the external reset line low, condemning the user port (modem) to a never-ending reset. Often users report a "frying egg" sound coming from the modem speaker. It is not a "bug". The easiest solution is to turn on everything, or disconnect it from the computer. If you want to make your C128 act more like a C64, there is a hack I described a long time ago- cut the trace at pin 3 of user port (/extres) and jumper user port pin 3 to pin 11 of U57 (inside the video can, VIC side). Normal disclaimers apply- do this at your own risk, etc. -- Fred Bowen uucp: {uunet|rutgers|pyramid}!cbmvax!fred arpa: cbmvax!fred@uunet.uu.net tele: 215 431-9100 Commodore Electronics, Ltd., 1200 Wilson Drive, West Chester, PA, 19380