3 Jun
2009
3 Jun
'09
9:10 a.m.
On Jun 3, 2009, at 12:03 PM, Ethan Dicks wrote:
Formally, yes, that's the max signalling voltage, but in practice,
there's a lot of 1488/1489 circuits powered by 7812s and 7912s out
there.
Very true; I was talking about the formal spec. I *think* the
spec actually says +3V to +15V and -3V to -15V, but I don't recall
for sure and I don't have it in front of me.
These devices had a lot of trouble with RS423, where
the voltage
was much
less than RS232. I don't recall the exact numbers but RS232 was
something
about 12V swings
+/- 15V I am pretty sure that the MAX232 can't get
things better than
about +/-10V (but I could be mistaken about that).
The MAX232, if memory serves, is specced at 10V but usually tops
out at 8-9V in my experience. I sure do love those chips. :)
-Dave
--
Dave McGuire
Port Charlotte, FL