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Serial Cable for Macintosh


To connect an Intelliox to an Apple Macintosh, a special cable is needed. If a so called modem cable nat avaiable, it is no problem so make it self. I bought a usual modem cable for PC with two male 9 pin connectors and cut one off. Then I soldered a Mini DIN 8 male connector to the cable, which fits to the RS-422 of the Macintosh. The table shows the different signals:

Macintosh Pin # Intellibox
Handshake out/DTR 1 CD
Handshake in/CTS 2 RX
TxD- 3 TX
GND 4 DTR
RxD- 5 GND
TxD+ 6 DSR
Gpi 7 -
RxD+ 8 CTS
- 9 -

The wires must be connected together like the graphic shows. Both connecters are shown from the soldering side. I choosed the colors of the wires by chance. The black wire is ground and the red one sends data from the Mac to the Intellibox. The green one receive data from the IBox. The orange wire is the CTS signal (Clear To Send). The pins 7 and 9 of the Intellibox are not connected , the pins 1, 6 and 4 are connected together. At the Mac the pins 4 and 8 must connected together to switch the serial port to RS-232. With this the Intellibox is usable with PC-setting (+12V CTS). There is no need to switch to Mac-setting (-12V CTS).

My old HyperCard software runs with 2400 bit/s with the Maerklin interface. I use the Intellibox with 19200 bit/s and the syntax "P50 and Intellibox" to use the standard commands and the extended commands of the Intellibox. How to set it is decribed in the manual.