On 9/3/2010 9:32 AM, schmidtd wrote:
> On Sep 3, 11:47 am, Eric Rucker<bhtoo...@gmail.com> wrote:
>> On Sep 2, 9:56 pm, schmidtd<schmi...@my-deja.com> wrote:
>>
>>> I'm not convinced the serial port is viable on my machine. I get the
>>> normal status out of the status register when nothing's attached, but
>>> when I hook up the other side via a null modem, the status doesn't
>>> change (at all) the way other SSC machines do. So, lots of tweaks to
>>> the configuration registers later, I still don't have anything coming
>>> out the wire.
>>
>> Could it possibly be TTL levels, rather than RS-232 levels?
>
> On a Commodore 64, sure - but this machine was made in 1996. The
> advertisements suggested that there was an upcoming communications
> package that would connect to the 'net, which would (at the time) have
> required a typical external modem at the other end of the serial port.
But perhaps they intended to add a level shifter in a special "cable".
It would be very helpful to look at the TX pin with a 'scope.
-michael
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