csg@pyramid.pyramid.com (Carl S. Gutekunst) (01/31/91)
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>
csg@pyramid.pyramid.com (Carl S. Gutekunst) (01/31/91)
In article <142964@pyramid.pyramid.com> I wrote: >The M-34 connector is fully metric. Wrong. The M-34 has the same problem as the DB-25: English threads in the U.K. and USA, and metric threads most everywhere else. (Stupid of me. Pyramid's own V.35 board uses English threads, as does our Cisco equipment.) <csg>