On 26-Jan-14, at 3:22 PM, Jeroen Roovers wrote:
Do serial cables deteriorate over time? :-)
Not much although the soldered/crimped connections could break. More
of an issue is the
drivers. Many boards use +3.3V devices such as the MAX3232. These
don't put out as much voltage
on the cable as standard RS232 drivers. So, they can't drive as much
cable as a fully standard device.
Secondly, the driver chips are sensitive to ESD damage (particularly
receiver). So, they could
get zapped, particularly if devices are connected while running when a
connection is made.
Currents can also flow through the cable when the grounds for the two
pieces of equipment
is the same. There is no isolation in RS232 so it is sensitive to ESD
problem. There is an 'E'
version of most RS232 driver devices which has improved (+15KV human
body) ESD protection.
I've seen quite a few devices die in the lab. The charge pump on
these devices is also sometimes
a problem.
Without a scope, it's hard to tell when the signals are bad. Best
that can be done is to test both
units with third device using same/different cables, etc.
Dave
--
John David Anglin dave.anglin@xxxxxxxx
--
To unsubscribe from this list: send the line "unsubscribe linux-parisc" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
