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#1 2017-07-07 02:51:31

MacOS Plus
Registered: 2015-12-09
Posts: 110

Xserve G4 serial port

First some interesting news from my experiments:

  As you know I've been booting one of my Rev.1 Xserve G4s into OS 9 as a result of development going on over at  One thing that had been nagging in my mind for a while was whether or not the built-in DB9 serial terminal/server management port was openly accessible in the typical manner of standard Mac serial ports under OS 9, since it would never appear as a device.  On a hunch I installed the driver extension file for the Stealth Serial Port to see if the Xserve's built-in port used the debug port trick in the same manner as the Stealth.  Well it turns out it actually does!  The port immediately was detected and appeared as a device in the AppleTalk control panel.  I managed to string together a cable to link-up an external MIDI interface and got it working using OMS.  So far no problems and it appears to be acting as a normal fully-functional serial port under OS 9.  Amazing!

  Now for a question.  When the Xserve is booted into OS X, the serial port appears as a device for a dial-up modem connection in the Network prefs pane.  The guys who wrote the Stealth driver for OS X also wrote a setup utility that sets up serial ports for use with OS X's native MIDI configuration utility instead.  I wondered if the third-party utility could be used to set the built-in serial port for MIDI.  Didn't work.  Then I wondered if the Stealth driver itself would help.  Also didn't work.  I presume that OS X's native driver is already taking control of the port and not letting any changes be made to it.  There's two things I don't know - do the Stealth driver and utility work in 10.5 or only up to 10.4?  Which native OS drivers are controlling the Xserve's built-in serial port?  I'm thinking that if perhaps I were to strip out the native serial driver then the Stealth driver might be able to take over and function just as I saw it do in OS 9.  Any ideas?


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