When the blue-and-white G3 arrived, Apple dispensed with its Mini DIN8 serial interfacing and went with USB. Newton users wept, QuickTake camera owners sighed and a multitude of StyleWriter printers spewed their last pages. Moreover, musicians were livid.
The Mac's serial port was used to connect to Midi interfaces that would, in turn, hook up with their music equipment that played from a software sequencer. Some serial interfaces, such as the Opcode Studio 5, could cost up to £800. With 15 Midi ports delivering 240 channels, it wasn't something you'd want to chuck out of the studio overnight. Various solutions appeared, returning serial port connectivity to new Macs running OS 9. The choice of serial adaptors consisted of USB converters, PCI cards and also individual ports that typically dispensed with the internal modem and utilised this connectivity to the motherboard.
The same range of third-party devices described above can offer serial interfacing for OS X, but finding a driver which functions with the serial peripheral gear is another matter. However, Gee Three has developed a specific Midi driver for use with its Stealth Serial Port hardware. Under OS X, the StealthMidi driver, together with the Stealth Midi Setup application, enables legacy serial Midi hardware to function with Audio Midi Setup (AMS), the Mac's music hardware routing utility, which has been available since OS X 10.2. Certain instances can affect functionality, so this workthrough provides specific steps to enable your legacy serial Midi interface to integrate with OS X and AMS.
Stealth Port hardware installation instructions are provided with the unit as it requires the removal of the internal modem from either a desktop Power Mac G3, G4 or G5 or any G3 iMac. You can't use the internal modem after installation. If the Mac can boot in OS 9, it will also work as a normal serial port (allowing AppleTalk connections too) and functions properly with Midi applications.
On OS X, the Stealth Serial Port needs to be activated from the Network control panel to work with serial peripherals. However, it needn't be turned on here to function with Midi, as the Stealth Midi Setup application will activate it separately, see step 8. If at some point the Stealth Port fails to be recognised by AMS, follow step 8 to check its assignment hasn't been lost.
Incidentally, some serial Midi interfaces provide synchronisation facilities such as a time code reader/generator. Generally, these features would be accessed via specific software utilities such as Opcode's OMS or MOTU's ClockWorks. While these functions should still perform properly in OS 9, they're not available within this OS X setup. With AMS, the Stealth Port software simply allows access to the Midi ports available on a serial Midi interface. Indeed, this is all most users need these days, as the time code functions are rapidly becoming redundant for mainstream music making. Particularly now that recording takes place within the Mac, rather than on an analogue tape machine with a time code track that the Mac would synchronise to. Hence, these functions are no great loss to most users.
However, shelling out up to £300 for an eight-port USB Midi interface isn't ideal, especially if you've already got a serial one. Recently, an Opcode Studio 5 was being offered second-hand for £50. Add another £50 for the Stealth Port and you get nearly double the connectivity for a third of the price and compatibility with older, serial Macs and OS 9. It makes Midi networking by Stealth hard to resist. [
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Author: Bob Dormon
Using Serial Midi interfaces on Mac OS X with the Stealth Serial Port