Apple ][ + but no Floppies

From: <(>
Date: Sun Dec 12 15:54:56 1999

>> It's a TTL device, not serial.

>The one does not preclude the other :-)

>The Apple mouse is TTL, and it's not serial (it's quadrature outputs as
>you said)

>A PC 'serial mouse' is serial (of course) and it's not TTL, it works at
>(approximately) RS232 levels

For some of us (including me!), our first brush with "serial" was 60mA current
loop data, a standard that I see you've ignored :-)

With some of the loop supplies being able to go up
to 50, 75, or even 100V in "open circuit" configuration, I'd *hate* to
see what would happen to TTL connected directly!

(I have to admit that I got started late enough that optoisolators were
the preferred way to go from current loop to other signaling levels... but
I do remember polar relays.)

 Tim Shoppa                        Email:
 Trailing Edge Technology          WWW:
 7328 Bradley Blvd		   Voice: 301-767-5917
 Bethesda, MD, USA 20817           Fax:   301-767-5927
Received on Sun Dec 12 1999 - 15:54:56 GMT

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