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A: Technical Specifications
Macintosh to MIDI Converter (DB-9 Female to MiniDIN-8 Female)
The Silicon Graphics Macintosh to MIDI converter converts the O2+ workstation’s
RS-232 Transmit Data and Receive Data signals to RS-422-like signalling used by MIDI
devices to connect to Apple Macintosh serial ports.
Table A-16 shows the pinouts for the O2+ workstation end.
Table A-17 shows the pinouts for the MIDI interface end.
Table A-16
Macintosh to MIDI Converter (DB-9 Female): Workstation End
Workstation Signal
Description
Pin Number
Voltage with Regard to Ground Required from or Supplied
to Workstation
DCD
1
Passed through from GPi
RXD
2
Supplies 0V typical low, +5V typical high
TXD
3
Requires 0V maximum low, 1.6V minimum high (RS-423)
DTR
4
Requires -12V maximum low to +12V minimum high
SG
5
0
DSR
6
Not connected
RTS
7
Re12V to power the converter
CTS
8
Passed through from handshake in
RD
9
Not connected
Table A-17
Macintosh to MIDI Converter (MiniDIN-8): MIDI Interface End
Macintosh Signal
Description
Pin Number
Voltage with Regard to Ground Supplied to or
Required from MIDI Interface Unit
GPi
7
Passed through to DCD
RXD
5(-) and 8
Requires -0.2V maximum low, 0.2V minimum high
TXD
32(-) and 6
Supplies -5V typical low, +5V typical high
HANDSHAKE OUT
1
Supplies -5V typical low, +5V typical high
SIGNAL GROUND
4
0
HANDSHAKE IN
2
Passed through to DCD