Macintosh IIfx: Serial Switch for Bypassing the IOP (6/97)


On the Macintosh IIfx, is there a way to disable or bypass the IOP (I/O Processor) that controls the SWIM and ADB, so that copy-protected programs that access the ADB hardware directly work properly?

I've been told that there is a cdev available that lets the user bypass the IOP for the SCC chip, enabling compatibility with serial devices that don't work with the IOP on the Macintosh IIfx. Is this true? If yes, where can I get this cdev?


There is no way to bypass the IOP that controls the SWIM and ADB.  The companies that sell the copy-protected programs need to modify their programs to work properly on the Macintosh IIfx.

It is possible to bypass the IOP that controls the serial ports.  Attached is a control panel called "Serial Switch" that makes this possible.  To bypass the IOP, just select "Compatible" in the Serial Switch control panel.

The cdev has two modes:

- Faster, when the IOP is used
- Compatible, enabling third-party developer's code to address the SCC
 hardware directly bypassing the IOP.

After choosing a different mode, you'll need to restart your system.

This software is available for individual use through online services that services that Apple post software updates to.

The CDEV is also available from Software Licensing for those developers who want to distribute it with their products.  The yearly fee is $50 per product it is to be distributed with.  No limit is set on the number of copies that can be distributed by a developer. For more information, search for "Apple Software Licensing" or call 408-974-1010.

These articles can help you locate software updates mentioned here:

* Where To Find Apple Software Updates
 Lists online services for "free" Apple software updates

* Obtaining Apple Product Support in the USA
 Lists 800 numbers and online services for software updates, Apple
 support information, and a subset of the Apple Tech. Info. Library



Published Date: Feb 18, 2012