2 Replies Latest reply: Dec 5, 2007 8:49 PM by William Spragens
ggm1960 Level 1 (0 points)
Long story short...is it possible to communicate with devices that want the old RS422 serial port on this computer.

Specifically, I'd bought the Lombard 333Mhz (OS 9.2.2) for the purpose of setting up a MOTU Midi Timepiece II. The MTPII has the RS-422(geoport, serial, 8DIN) connection but I discovered that the Lombard doesn't. No problem I thought so I also bought a Compu-Cable Mini-Geo USB to serial port adapter but that caused the computer to lock up whenever I searched the idock ports with the MTP unit turned on, otherwise it says it doesn't see anything on the port(s).
The MOTU unit is not suspect because I have another known good model and I get the same results when attempting to access it. The geo-port adapter seems to be installed correctly.

I've seen it mentioned that on comparable desktop models some sort of Stealth card needs to replace the internal modem.

I'm new to macs but very experienced with PCs. Is there a way to change settings or disable conflicting devices to make this work? Try a different OS or adapter, or am I SOL?

Powerbook G3 Lombard 333Mhz, Mac OS 9.2.x
  • jpl Level 7 (28,285 points)

    Welcome to the Discussions.

    I don't have your answer, but I would suggest you head over to the MacOS 9 Discussions where you will find some very experienced contributors who are familiar with these software/peripheral issues.

  • William Spragens Level 2 (200 points)
    For the MOTU interface to work, you need a serial port which can accept an external clock. I doubt any USB->Serial adapter can do that, since USB is a half-duplex connection (data goes one way at a time) and you need clock going to the Mac and MIDI going from it at the same time.

    For desktop Macs, there was a gadget made called a "Stealth Port" by Gee 3 which replaced the modem PCB with a line driver chip and an 8-pin DIN port. I don't know if there is any such animal for PowerBooks, or if one of the desktop variety could be hacked into place. The Blue & White G3 modem looks very similar to the one in my Wallstreet, so it might be possible.

    My guess is, it'll be much easier to get a USB->MIDI adapter for the Lombard. Or if you're set on the MOTU Timepiece, get a Wallstreet G3 PowerBook which has an old skool serial port and SCSI and all the other old fashioned amenities.