19 Jun
2013
19 Jun
'13
6:23 p.m.
On 06/19/2013 06:53 PM, Fred Cisin wrote:
The most common is really bad static. I've also seen people pulling
RS232 plugs
with either piece live, if ground is the pin that breaks first then you
may 24V at
the wrong place.
The other is safety ground that has potentials from one outlet to another.
Most common reason for that is neutral and ground swapped or a peice of
gear using ground instead of neutral for the return.
I've seen more than a few outlets in NYC and other places where from the
ground pin
on one outlet to an outlet ground pin on a different breaker had 25V
AC! I even
had one that had 119Vac (ground and line swapped!).
Be very careful what you call ground.
Allison
>> I know
that the 1488/1489 combo was popular, but the lead engineer on
>> the comms project at the time that I was involved insisted that the
>> 75150/75154 combination was much superior. I don't recall what his
>> reasoning was, but we didn't run into any popped 7515x parts that I can
>> remember.
> How well did those withstand a "centronics" parallel printer being plugged
> into the serial port (with a gender changer?)?
On Wed, 19 Jun 2013, Tony Duell
wrote:
Any RS232 port will withsand the TTL signals on a
Centronics port. If it
doesn't, it doesn't; comply with the RS223 standard :-)
However, the Centroics Printer (or at least the input buffers on its
interface) are not going to like having 12V RS23 signals shoved into them.
I suspect the printer will emit the magic smoke, not the RS232 buffers
thanks
I wonder what else our lab staff was doing that kept blowing 1488/1489
chips?