midkiff@portia.Stanford.EDU (Neil Midkiff) (01/13/91)
I have a problem with the modem port on my Mac IIfx. After running the MIDI sequencer program EZVision from Opcode Systems, the port appears to be "damaged" for normal data-modem use. Specifically, I can send ASCII to the modem (proved by the fact that it will accept Hayes dialing commands, etc.) but no ASCII data comes back from the modem (no command echoes or OK's). The modem itself is working, since I can use it perfectly well from the printer port, when I set the communications program (Quick Link II) to use the printer port. The modem port works for both input and output in MIDI mode using Opcode's MIDI Translator interface with my keyboard and tone generator. The software seems to work "as advertised"...that is, upon exiting EZVision, the ports are freed up for other programs now. [This was not initially the case; at first, EZVision had to be ["helped" by manually disabling MIDI for the serial port [before quitting the program. Then I found a copy of Apple's [MIDI Manager (on the Lime distribution from U of Illinois) [and installing that fixed the problem. Alternatively, [Opcode's MIDI Init will also make the port-freeing automatic. However, nothing I can do (including zapping the PRAM) seems to fix the one-way data modem problem. Can anyone explain to me whether some strange sort of hardware defect can allow MIDI to work on input and output but RS-422 ASCII only on output? Additional info: System 6.0.5 (recently reinstalled from distribution disks), IIfx Serial Switch cdev set to "Compatible" mode. Does anyone know where I can find documentation for the MIDI Manager? Immense, heartfelt thanks to anyone who can provide any help at all. I can still function by using the modem from the printer port, but that involves unplugging the printer and disabling AppleTalk every time I want to log in to the mainframe I'm using now, and reversing the process for printing. I didn't expect to have to devote one serial port permanently to MIDI. -Neil
dbell@cup.portal.com (David J Bell) (01/13/91)
Neil: >I have a problem with the modem port on my Mac IIfx. After running >the MIDI sequencer program EZVision from Opcode Systems, the port >appears to be "damaged" for normal data-modem use. Specifically, I >can send ASCII to the modem (proved by the fact that it will accept >Hayes dialing commands, etc.) but no ASCII data comes back from the >modem (no command echoes or OK's). >The modem itself is working, since I can use it perfectly well from >the printer port, when I set the communications program (Quick Link >II) to use the printer port. >The modem port works for both input and output in MIDI mode using >Opcode's MIDI Translator interface with my keyboard and tone >generator. I'm not familiar with the interface you're using, nor with the software, but this sounds an awful lot as if something (a still- resident MIDI driver, for instance) is trapping received data interrupts on the COM port. Properly behaved software should not service interrupts from a device that it is not currently using, but this type of error is not uncommon between different programs co-residing in the O.S... Maybe someone with more MAC MIDI experience can tell you more. Dave