🚀 go-pugleaf

In article <42894@cos.com> howard@cos.UUCP (Howard C. Berkowitz) writes:
>Instead, people use X.21 _bis_, which is more or less RS-232C.
>[Actually, X.21 bis points to the physical connector specification in
>V.24].

As long as you're being pedantic.... :-)

X.21bis was intended as an "interim" standard, documenting existing practice
in the United Kingdom and North America, with the assumption (in 1976) that
some day all those folks would wise up and use V.10/V.11 (the hardware parts
of X.21). Of course, the status quo hasn't changed in the least since 1976,
and if anything has gotten worse, as more and more people run RS-232C up to
72Kbps and V.35 at T1 speeds.

X.21bis refers to V.24 and V.28, which together are roughly equal to RS-232C;
the 25-pin D connector we all know and love is specified in ISO2110. X.21bis
also refers to the electrical interface portion of V.35; an oddity since as of
1988 CCITT no longer publishes V.35. The common M-34 connector is specified in
ISO2593. It is in ISO2110 where the problems with English vs. Metric threads
arises. The M-34 connector is fully metric.

<csg>