MAP@AI.AI.MIT.EDU.UUCP (09/01/87)
James Starr writes:
The RS-232C standard is undoubtedly the most corrupted and bastardized
standard in the world. In fact the only thing I have not seen changed
is the physical size of the connector, the pin spacing and pin 7 being
signal ground.
I have even seen these changed!!! The RS232 standard is a marvel of
ambiguity. The only thing it clearly seems to state is what the
voltage levels are (for high and low, it is occasionally unclear as to
which is True/False or 0/1). It seems to be sufficiently carefully
worded that anybody who reads it gets a clear unambiguous meaning,
however not everyone gets the same one. In over 10 years of working
with ``RS232 compatible'' devices, I have found that immediate
inter-operability between different vendors was the exception rather
than the rule. This is partially supported by the growing market in
companies supplying interconnection, usually cables with funny wire
swaps, but even fancy boxes to translate RTS/CTS to XON/XOFF and
similar things. I have always read the phrase ``RS232 compatible'' as
meaning an experienced RS232 hacker can probably get simple
functionality in less than 1 whole day. Complete functionality is, of
course, a different matter and has been known to require weeks or even
months of tweaking to get it right.