Writing pins to the RS232

[Richard Brodie]

"Roy Smith" <roy at panix.com> wrote in message 
news:roy-D8EE56.19040027112005 at reader2.panix.com...
> "jay.dow at gmail.com" <jay.dow at gmail.com> wrote:
>> While I realize this is more on a driver/hardware level it's
>> interesting that it's so difficult to use a different protocol for an
>> existing driver.  For example, all serial does is a series of high and
>> low voltages on specific pins.  Why should it be so hard to use an
>> existing driver and hold a pin on high?
>
> It's been a long time since I've looked at this low-level hardware, but 
> the
> answer is almost certainly, "No just 'so hard', but 'impossible'".

If you just need one or two signals, then it might be practical to use one
of the control lines, and PySerial supports this (UPS monitoring software
often works this way). Setting 8 pins to 1 would be impossible, because
there plain won't be that number of outputs wired, in addition to all the
good stuff about UARTs Roy said.