[rescue] SCSI-Ethernet on an 68040 Macintosh

Nate nate at portents.com
Mon Jan 17 23:09:17 CST 2011

On Jan 17, 2011, at 11:29 AM, gsm at mendelson.com wrote:

> On Mon, Jan 17, 2011 at 11:13:25AM -0500, Patrick Finnegan wrote:
>> On Monday, January 17, 2011, gsm at mendelson.com wrote:
>> Why can't an Apple 2 read "Apple 2" 5.25" GCR disks?
> It can. It's just that connectivity is pretty poor unless you use a IIgs.
The best you could get on a IIe was 9600 bps, and IIc was flakey at 1200.

Regarding the IIe, it depends on the serial card - the original Apple II
Communications Card supported selectable speeds that topped out at 4800 bps.
The most common serial card, the Apple Super Serial Card, had a documented max
of 19,200 and undocumented register settings that let it run at 115,200:


The only Apple //c computers that had a problem above 1200 baud were the ones
manufactured between April 1984 and December 1984, when Apple used a 74LS161
to divide the clock for the serial ports, which was 3% too slow.  Apple
changed that to an oscillator on motherboards produced from 1985 onward, and
replaced any original motherboards at no charge at customer request when
someone experienced an issue above 1200 baud on older motherboards.

The Apple //c+ and IIgs had no serial port issues.

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