15 Jun
2012
15 Jun
'12
9:25 p.m.
On 14 Jun 2012 at 17:30, Dave McGuire wrote:
Sure. But thwre's a bnig differnece iMHO between an RS232 driver that can
be shut down to save power if the interface isn't being used, and one
that is controleld by an RS23 input. The formr is useful. The latter is
pain, if on;y because you presumably can't conenct 2 such machines
together (bneither will power up irs drvier because the other machien's
driver isn't pwoered up so the necessary input signal is not asserted).
-tony
Just to jump in...I don't know about
machines, but at least one of
the
later MAX232 family chips can be configured to do this. It's a
power-saving measure; it shuts down the charge pump. Note that this
is not the "MAX232", but one of that family, which comprises upwards
of thirty completely different chips now.
Linear Technology EIA transceivers ; e.g. LT1080--pretty much have
always had that feature--with an ON/OFF pin.