\pard\tx520\tx1060\tx1600\tx2120\tx2660\tx3200\tx3720\tx4260\tx4800\tx5320\f0\b0\i0\ul0\fs28\fc1 MIDI Macintosh Serial Cables RS232 RS422\
\
Q: How can I get a MIDI interface to work with the new 68040-based NeXT computers?\
Q: What cable do I need to connect between the 68040 serial port and a Macintosh-compatible serial device?\
\
A: NeXT changed the serial ports on the 68040-based systems to support hardware flow control, which is an important feature for modems. The old ports were RS-422 format, and the new ones are RS-423, which is RS-232-compatible. While this change won't affect all devices, some devices will no longer work with a standard Macintosh serial cable, including most MIDI interfaces. The symptom is that MIDI works in one direction only (in but not out, or vice versa), or not at all. \
\
Macintosh-style MIDI interfaces that adhere rigorously to the RS-422
\pard\tx520\tx1060\tx1600\tx2120\tx2660\tx3200\tx3720\tx4260\tx4800\tx5320\fc1 should also work with the new RS-423 serial ports, if the right cable is used (see below). However, most MIDI interfaces don't work, even with the new cable. Rupert Nieberle of Realtime Computing and Nets, in Berlin (phone: 49-30-6187765
, fax: 49-30-6116774
), manufactures
a
moderately priced
MIDI interface that
is
compatible with both 68040-
and 68030-
based machines, using standard cables. \
\
A more elaborate MIDI interface that is known to work (with a custom cable) is the Studio 3 from Opcode Systems.
\pard\tx1140\tx2300\tx3440\tx4600\tx5760\tx6900\tx8060\tx9200\tx10360\tx11520\fc1 Opcode Systems may provide other solutions, including the modification of existing Pro Plus interfaces to work with 68040-based NeXT computers using standard serial cables.
\pard\tx520\tx1060\tx1600\tx2120\tx2660\tx3200\tx3720\tx4260\tx4800\tx5320\fc1 The appropriate cable for the Opcode Studio 3 is the last one given in the
\b zs
\b0 man page ("NeXT 68040 to Some RS-422 Devices"). It's available from Computer Cables and Devices in Connecticut; ask for part number CCD 1137 (which they also refer to as the "unlike" cable, in contrast to the "like" cable used to hook two 68030 machines or two 68040 machines together). See NextAnswers hardware.470 for more information about this company.\
\
We've seen some cases where the cable given in the man page didn't seem to work with the Studio 3, while the following cable did:\
\
\pard\tx1140\tx2300\tx3440\tx4600\tx5760\tx6900\tx8060\tx9200\tx10360\tx11520\f4\fs24\fc1 040 Mac Peripheral\
Signal pin pin Signal\
------ --- --- ------\
RxD- 5 3 TxD-\
TxD- 3 5 RxD-\
n/c 6 8 RxD+ ----+-- tied together\
Gnd 4 4 Gnd ----|\
n/c 8 6 TxD+ ----+-- tied together\
CTS 2 1 DTR\
DTR 1 2 CTS\
? 7 7 ?\
\f3 \
\f0\fs28 The pins are numbered as follows, looking at the pins from the outside of the connector:\
\f4\fs24 \
6 7 8\
\
3 4 5\
\
1 2\
\f3 \
\f0\fs28 One customer reported that the above cable worked only if he reversed it (so that the NeXT end went to the peripheral and vice versa). Another customer reported that the following cable works with an inexpensive MIDI interface (the Opcode MIDI Translator). We haven't verified either of these approaches; use at your own risk. (But if you do try them, please send a message with your findings to NeXTanswers@next.com, mentioning NeXTanswers hardware.580.)\
\
\pard\tx520\tx1060\tx1600\tx2120\tx2660\tx3200\tx3720\tx4260\tx4800\tx5320\f4\fs24\fc0 NeXT MIDI Translator\
