I thought this topic deserved its own thread separate from the one about booting the Xserve into OS 9:
I had been wondering for the longest time about whether or not the built-in DB9 serial terminal/server management port on the Xserve could be accessed directly by the operating system as a normal Mac serial port. Due to other priorities I'd never got around to testing that possibility, that is, until today. I suppose since Nanopico and I are likely the only members here who have even been booting Xserve G4s into OS 9, this sort of testing was probably never attempted before.
I started with the premise that the Xserve serial port is not a 'standard' Mac serial port in the traditional sense since it never showed up as an available port in the AppleTalk device list. This suggested to me that it might be wired via the debug port in the same manner as a Stealth Serial Port. Since the Stealth device is just a serial transceiver, the Stealth driver extension file is what actually does the work of enabling the serial port configuration of the debug port. With this in mind, the first thing to try was installing the Stealth extension file and seeing if the Xserve serial port appeared in the AppleTalk control panel. Amazing discovery - HOLY SH*T it did!
Next was to prove that it actually worked properly. I decided the first thing I would try was a MIDI interface since that was my primary goal for use of the Xserve serial port. The challenge was coming up with a cable to get from the DB9-M on the machine to the DIN-8 port on a MIDI interface. I scrounged around in everything I had both Mac and PC. The end result was a DB9-F/DB25-M cable, a DB25-F/DB25-F gender changer, and then a DB25-M/DIN-8-M Mac modem cable. This yielded no device detection by OMS, but, remembering that Mac DIN-8 cables have crossover wiring, I figured I'd better try crossover wiring. This was accomplished by adding yet more to the cable chain - a Mac DIN-8-F/DIN-8-F switchbox as a second gender changer, followed by a standard Mac DIN-8-M/DIN-8-M serial crossover cable.
I'd started out with an Opcode Studio3 MIDI interface as the target. It blinked a lot during OMS detection but never showed up in the studio setup window. This activity did give me hope however. I decided to go with something a bit simpler - an ancient JL Cooper SyncMaster. SUCCESS! It was detected as a generic MIDI device. Next I installed Band-in-a-Box so I could generate some simple instrument MIDI data output and hooked up a drum machine to the MIDI out. IT WORKED! The drum instrument panel controlled the external drum machine as it should have, as did playback of demo songs. Using a MIDI keyboard on the input and routing through back out to the drum machine also worked, proving all the communication in and out works.
So, super cool - I essentially just gained myself a 'Stealth Serial Port' on both my Xserves for a grand total cost of ZERO DOLLARS! This was tested using the 1.0.3 version of the Stealth OS 9 extension. Presumably the Griffin gPort driver also works the same. Does anyone know what the situation was with support for OS X 10.5 on either of those products? I'd like to test that with the Xserve under 10.5 also if the drivers were available.
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Topic: Xserve G4 - Using built-in DB9 serial port under OS 9 (Read 10203 times)