[comp.sys.amiga] using a 1000 midi interface on a 500

janzen@ant.dec.com (Tom 296-5421 LMO2/O23) (07/27/88)

Subj:	mimetics interface works

The Mimetics interface for the Amiga 1000 (which I am borrowing from a friend)
was not compatible with the A500
for a few reasons.  The gender of the connector was wrong.  The A500 has
a DB25-P on the back.  The 1000 has a -S.  Another reason was, that
although the pin assignments are the same for data (TXD and RXD),
the -5V and +5V are assigned to different pins.
Here's a simple chart:

MIDI inte	A1000	A500
21		+5	9
2		TXD	2
3		RXD	3
7		gnd	7
14		-5	10

I built my interface cable to connect a DB-25S with the 500 pin out
to a DB-25S with the 1000 pinout.  The cable used a mass-terminated
ribbon connector on the 1000 end and a solder tab or cylinder connector
on the 500 end, and a ribbon cable (25 conductor).  The pin numbers
are printed on the connectors.  I also had to build a straight-thru
DIN plug to DIN plug pin 4 to pin 4, pin 5 to pin 5 (why doesn't LaSalles
in Boston have plug-plug DIN adapters?) to connect the interface to
a midi box.
My interface works now from DMCS with no extra software beyond DMCS.
Thanks
Tom Janzen Digital Equipment 111 Locke Marlboro MA 01752