🚀 go-pugleaf

[This is actually a snippit from the "loyalty pays upgrade in Canada"
discussion, but I've changed the subject line, and included
comp.dcom.modems where followups are re-directed to.]

In article <1992Jul20.052318.29102@zooid.guild.org> Ross Ridge <ross@zooid.guild.org> writes:
> peters@beltrix.guild.org (Peter Sleggs) writes:
> >I use USR V32bis for my uucp connections and I have no end of trouble
> >with T2500's that have MNP enabled, but otherwise they work OK. uunet.ca
> >has worldblasers and they seem to work just fine.
> 
> ZOOiD's T2500 has MNP enabled, at least it should.

Anybody running MNP at any level with UUCP 'g' should have their modem
and UUCP configurations examined!  :-)

MNP-4 is link-layer protocol that retries erroneous packets.  UUCP 'g'
is a link-layer protocol that retries erroneous packets.  Guess what
-- the don't get along very well!

MNP-5 is a compression scheme.  I don't believe you can have MNP-5
without also using MNP-4, i.e. don't try to use MNP-5 with UUCP 'g'.

On the other hand, you do want to *allow* (but not force) MNP for
dial-up, in case it's a human, or co-operating protocol like SL/IP.
So, you must disable your modem's MNP when you dial out (i.e. from
Dialers) with uucico, but *not* with cu.  This is easy with newer
HDB's that have the Sysfiles configuration stuff, and you can set up
separate Devices and Devices.cu files, thus the same class of device
can be configured to use a different Dialers script.

BTW, so far as I know, the V.42bis compression protocol is quite
useful in conjunction with UUCP 'g', especially on a modem that does
local spoofing of the 'g' protocol (such as the T-2500).

The Addendum for the WorldBlazer talks about the Telebit LZ Data
Compression scheme, and hints that V.42bis can be used with PEP.  It
does not say if Tb's LZ is "safe" with pre-compressed data (like LAP-M
is).  [V.42bis, MNP-5, and LZ are all variants of the Lempel-Ziv
compression algorithm, though most implementations of MNP-5 *reduce*
throughput with pre-compressed data, and each have varying degrees of
efficiency and ratios of compression.]
-- 
						Greg A. Woods
woods@Elegant.COM, woods@robohack.UUCP  VE3TCP	ECI & UniForum Canada
+1-416-443-1734 [h]  +1-416-595-5425 [w]	Toronto, Ontario; CANADA
Political speech and writing are largely the defense of the indefensible-ORWELL