17 Jun
2013
17 Jun
'13
8:04 p.m.
On 6/17/2013 8:52 PM, Mouse wrote:
I'm not sure what's supposed to be unfriendly about RS-232C. The major
unfriendly part there, it seems to me, is the space in the middle, -3V
to +3V IIRC, for which the logical signal state is undefined.
I read earlier post as USB being friendly.
232C and USB are both bit serial, but USB has higher
speeds,
friendly voltage levels, power from a host included and well-defined
protocol.
I question friendly voltage levels. 3.3 volt powered logic and chips
came just after them if I recall correctly. Though I suppose it's a question of "friendly
to what/whom"....
The part of RS-232C I _really like_ is the impedance spec, the part
that says that any pins or combinations of pins may be shorted to one
another or to any voltage source within, I think, the valid RS-232C
voltage range (-15V to +15V or some such - I forget the exact limits),
with the shorts maintained indefinitely, without damage.
I also like the splitting of protective ground and signal ground.
You'd almost think it had actually been designed by competent
electronics engineers or somethin'....
True.
/~\ The ASCII Mouse
\ / Ribbon Campaign
X Against HTML mouse at rodents-montreal.org
/ \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B