RS232C is such that if the voltage swings +/- 6V it is in compliance.
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----- Original Message -----
From: David Kelly Date: Thursday, December 15, 2005 3:20 pm Subject: Re: [AVR-Chat] Re: PC COM Ports > On Thu, Dec 15, 2005 at 10:34:00AM -0600, Thomas Keller wrote:> > John Samperi wrote:
> >
> > > At 05:52 AM 15/12/2005, you wrote:
> > > >0/+3 happens to work on classic 1488/1489 buffers, "but its
> not right."
> > > >
> > > >Super serious workstations used to rigidly ahere to +-10 volts.
> > >
> > >
> > > + - 25V being the 'right' voltage :-)
> >
> > Uhm...IIRC correctly, the RS-232C specification reads that the
> signal
> > voltages are to be +/- 12.5 VDC (25 v total across the two).
>
> There are a lot of places in the net with a lot of conflicting EIA-232
> information. Most likely due to the $100 fee for downloading the real
> document. Maybe why there are so many bad implementations. +-15
> and +-25
> volts are the most common max voltages quoted.
&! gt;
&