Path: utzoo!mnetor!uunet!husc6!im4u!ut-sally!pyramid!csg From: csg@pyramid.pyramid.com (Carl S. Gutekunst) Newsgroups: comp.unix.wizards Subject: Re: UUCP over X25 on Sun 3 Message-ID: <20060@pyramid.pyramid.com> Date: 19 Apr 88 06:08:32 GMT References: <287@tauros.UUCP> <19772@pyramid.pyramid.com> <18341@watmath.waterloo.edu> Organization: Pyramid Technology Corp., Mountain View, CA Lines: 26 In article <18341@watmath.waterloo.edu> egisin@watmath.waterloo.edu (Eric Gisin) writes: >I think there is also an 'x' protocol, which uses X.25 directly >and can use all 8 bits. 'f' was designed for use over X.2[89], >which has the 7 bit restriction. 'x' provides no error correction at all, and does not permit in-band flow control (XON/XOFF). It is suitable only for simple point-to-point links using dedicated internal X.25 hardware. The 7-bit-printable-ASCII restriction comes from international X.25 gateways, many of which insist on swiping the eigth bit for parity or somesuch. A few also do funny mappings of control characters, like munging tabs. If I set up a raw X.25 virtual circuit between here and West Germany, it will be 7 bits and there is nothing I can do about it. The X.29 and X.28-1980 standards require 8-bit transparency. Not until 1984 is there any mention of DTE-to-PAD parity generation (X.3 parameter 21), and it is disabled by default. Note that everyone who connects to uunet for UUCP via dialup Tymnet is using the 8-bit 'g' protocol over X.29; similarly, we run 'g' over X.28 PADs all the time. (Of course, we have to disable flow control on parameters 5 and 12. But calling into a Pyramid, it does that automatically.) Finally, many sites (e.g., munnari) run 'f' right on top of X.25, and don't bother with the hassle of X.29 at all.