On Tue, 25 Dec 2001, John Waters wrote:

> Hi All,
>
> I'm designing a portable data logger. From time to time, the user has to
> bring the logger to a PC and transfer the collected data to it. I want to
> use the serial port in the PC as the interface, but I worry that the RS232
> drivers may be spoiled quickly, since most of the time the RS232 plug is
> inserted or removed when the computer is still on. I can tell the user to
> turn off the power first but I don't think they will follow! Is there any
> solution? Are there better ways to transfer data back to a PC? The interface
> can be anything and doesn't just restricted to the serial port.

Well...  USB is specifically designed for hot insertion, but I really
wouldn't worry about it.  In 20+ years of dealing with every kind of
serial port known to mankind, I've never seen a problem with connecting
powered up RS232/EIA-232 devices.  I've dealt with multiport terminal
concentrators and modem racks where it was not unusual to connect and
disconnect devices regularly, and I don't think there were even notices
from the normally paranoid manufacturers to only connect deviced with
power off.  The drivers & receivers are designed to take a lot of abuse.
If it's really a concern, power the datalogger off before connecting it.

Dale

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