Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[smilesdavis]

Macintosh Serial MIDI: Hardware Evolution
Macintosh model / serial hardware ↔ serial-MIDI technology

Year	Macintosh hardware	Serial / MIDI development
1984	Macintosh 128K / 512K	Zilog Z8530 SCC; two channels = modem + printer; DE-9 Macintosh differential serial; TxD± / RxD±; limited external handshake/clock signals.
1986	Macintosh 512Ke	Retains original DE-9 SCC serial architecture.
1986	Macintosh Plus	Mini-DIN-8 introduced; TxD± / RxD± / HSKo / HSKi. HSKi pin 2 = handshake or external SCC clock. GPi pin 7 not connected.
1987	Macintosh SE / Macintosh II	Mini-DIN-8 becomes standard; two SCC ports = modem + printer. GPi added; modem-port GPi can provide an additional SCC clock path. HSKi remains external TRxC clock input.
1987	—	Apple System Peripheral-8 Cable M0197: Mini-DIN-8 ↔ Mini-DIN-8; later specified for Yamaha TG100 and Opcode Studio 5.
1988	Macintosh IIx	Two-port Mini-DIN-8 SCC; HSKi external clock + modem-port GPi clock path.
1989	SE/30 / IIcx / IIci / Macintosh Portable	Mini-DIN-8 SCC; HSKi external clock; GPi available with additional modem-port clock routing.
1990	Macintosh IIfx	Full Mini-DIN-8 SCC implementation; HSKi + GPi clock paths.
1990	Macintosh Classic / IIsi / LC	Mini-DIN-8 retained; GPi absent on these implementations; HSKi pin 2 remains external SCC clock input.
1991	Classic Mini-DIN-8 Macs	Yamaha TG100: external 1 MHz → Mac HSKi; 8-bit / 1 stop / no parity; MTP OFF; M0197 cable.
1992	68K Macintosh SCC generation	Opcode Studio 5: Peripheral-8-equivalent cable; MTP emulation.
1993	Centris 660AV / Quadra 840AV	GeoPort introduced: 9-pin socket accepts Mini-DIN-8; pins 1–8 retain serial signals; pin 9 = power; synchronous/DMA functions added.
1993	Classic serial + early GeoPort Macs	Roland RSC-15APL: straight Mini-DIN-8 ↔ Mini-DIN-8, 1 MHz. Kawai K11: direct Mac serial, 1 MHz. E-mu SoundEngine: Mac sound module + MIDI-interface routing. Opcode Studio 4: MTP interoperability using its own host protocol.
1994	Power Macintosh 6100 / 7100 / 8100	68K → PowerPC transition without abandoning Macintosh serial; existing serial MIDI hardware remains usable.
1994	PowerBook 500 series	One external Macintosh serial connector replaces separate modem + printer sockets.
1995	PowerBook 190 / 5300	One Mini-DIN-8 serial port; LocalTalk retained.
1995	PowerPC / late-68K serial Macs	Yamaha MU50: 1 MHz; F5 Cable Messages; Port 1 internal, Ports 2–8 thru. Korg X5DR: AG-002; 31.25 kBPS serial data; 1 MHz application clock; KORG MIDI Driver; F5 line-control commands.
1996	PowerBook 1400	One full Mini-DIN-8 Macintosh serial port; synchronous / asynchronous / AppleTalk; HSKi / HSKo / GPi / Tx± / Rx±.
1996	Serial MIDI at peak maturity	Generalmusic WK4: Mac serial, 1 MHz, 16 channels. Alesis QS/QSR: 1 MHz → HSKi; bit-clock determines serial rate. MOTU MIDI Timepiece AV: 8×8 serial; MTP networking.
1997	Power Macintosh G3 Beige	Final desktop Power Mac generation with factory Macintosh modem/printer serial ports.
1997	Late classic serial Macs	Yamaha MU100: 1 MHz; MTP ON; F5 Port 1 = A1–A16, Port 2 = B1–B16; 32 parts. Korg NS5R: 31.25 BPS mode + 1 MHz clock; F5 01/02/03 routing. Emagic Unitor8: MTP emulation; 1 MHz / FAST; F5 cable messages; AMT.
1998	PowerBook G3 Series / Wallstreet	Final high-performance PowerBook with factory serial/GeoPort; synchronous + asynchronous; HSKi external clock; up to 4 Mbps serial hardware.
1998	iMac G3	USB transition: Macintosh serial and ADB removed.
1998	USB / internal replacement ports	Compatibility splits: Griffin iPort / KeySpan USB Serial Adapter lack Unitor8 external-clock support; GeeThree Stealth / Griffin gPort provide modem-port-compatible FAST + AMT operation. iPort still works with less demanding interfaces including Opcode Studio 5.
1999	Power Macintosh G3 Blue & White	Factory Macintosh serial removed; USB / FireWire / PCI replacement era.
1999	PowerBook G3 Lombard	Serial/GeoPort removed; USB replaces legacy serial connectivity.
1999	Serial-less Macs + remaining legacy Macs	Technics SX-PX332: SZ-JJAP1 Mac cable, 1 MHz. Midiman BiPort 2x4s: printer/modem serial, OMS. Keyspan SX Pro: 4× RS-422, 1 Mbps, printer-port emulation. MegaWolf Romulus/Remus: PCI serial MIDI via FreeMIDI.

Technology progression

Macintosh side	MIDI / protocol side
DE-9 SCC	Basic Macintosh differential serial
Mini-DIN-8 + HSKi	Externally-clocked serial HOST connections become practical
GPi / additional SCC clock routing	More flexible synchronous serial hardware
1 MHz HOST transport	Yamaha / Roland / Kawai / Alesis / Generalmusic / Technics direct COMPUTER connections
GeoPort	Legacy serial retained + synchronous/DMA extensions
PowerPC + classic serial	OMS / FreeMIDI serial ecosystem continues unchanged across CPU transition
F5 host-control framing	Yamaha / Korg / MTP-compatible virtual-port routing
MTP compatibility	MOTU native; Opcode / Emagic compatibility or emulation modes
FAST / AMT	Emagic native high-speed/timestamped serial operation
USB replaces SCC serial	Baud-rate support alone no longer guarantees MIDI-interface compatibility
PCI / internal replacement ports	Compatibility depends on electrical implementation + external clock + Macintosh port emulation + driver/API

Key distinction:

Mini-DIN-8 ≠ cable topology ≠ host protocol
1 MHz clock ≠ serial data rate ≠ MTP
F5 xx = host-control / virtual-port framing
MTP compatibility ≠ native MTP implementation
USB serial ≠ Macintosh SCC