Path: utzoo!attcan!uunet!mcvax!hp4nl!gouldnl!ted
From: ted@gouldnl.UUCP (Ted Lindgreen)
Newsgroups: comp.dcom.modems
Subject: Re: TrailBlazer and UUCP
Keywords: UUCP trailblazer
Message-ID: <647@gouldnl.UUCP>
Date: 1 Aug 88 10:40:02 GMT
References: <311@mikros.systemware.de>
Reply-To: ted@gouldnl.UUCP (Ted Lindgreen)
Organization: Gould European Unix Support Centre
Lines: 70

In article <311@mikros.systemware.de> stefan@mikros.UUCP (Stefan Stapelberg) writes:
>SINIX (derived from SIII).  As far as I can tell, the UUCP version
>available from Siemens will support 'g' and 'f' protocol.
>
>Are there any restrictions concerning transmission speed and/or
>error recovery with this antique version of UUCP?

If you use the standard setup (g-protocol) I don't see any
problems.
>How about 'f' protocol? Does it work reliable? (e.g. what happens
>if there is noise on the line between the modem and the computer?)

The f-protocol is usable as well, but you need to setup flowcontrol
on both sides. The trailblazer is among the best modems there are
to deal with noisy telephone lines. Normally we get speeds between
11 and 15 kbaud, I have seen this to drop to 7 kbaud on a really
noisy line. The PEP protocol garanties errorfree data transmission.

>I am very appreciated for any pointers/hints.
OK,

The g-protocol does not need flowcontrol. Hardware flowcontrol does
not harm generally, but software flowcontrol must NOT be used.
This is because the g-protocol uses full 8-bit characters. ^S or ^Q
characters, produced by modems or terminal drivers will break the
protocol.
I have heard about situations where the full speed is not reached
with hardware flowcontrol, but I have not seen that myself.
Enable UUCP (S111=30) and turn off flowcontrol (S58=0 S68=255).
For compressed news, I have seen an improvement of 10% if
compression is turned OFF (S110=0).

The f-protocol (switched on if the LINE field is PAD) needs error
free transmission and perfect flowcontrol. Error free transmission
is OK with trailblazers. Flowcontrol can be either hardware or
^S/^Q, but it has to be setup properly on both sides.
The f-protocol maps all characters in the range of printable
characters. Effectively, this means, that ASCII data (email) is
almost unexpanded, but binary data (compressed news) is expanded
with 50 to 75%. The raw speed with the f-protocol is a few percent
higher than with the g-protocol (provided data compression in the
trailblazer is enabled). So for email you gain a few percent, for
netnews you loose a lot.

The fastest protocol is the t-protocol (if you can switch it on,
you need to change uucico to do that).
This protocol sends 8-bit data in chunks of 1 kbyte. It will
work only with hardware flowcontrol on both sides.
You will gain a few percent on both binary and ascii data.
However, the end of the uucico session may fail as a TCP
connection is stopped in a different way.

Concluding I would advice: use the standard g-protocol.
The possible improvement with f- or t-protocol is only marginal.

I use a fixed interface speed (19200) and hardware flowcontrol
normally. To change the Trailbazer settings for a particular
uucico session (we talk to different types of modems in various
countries), I put the special settings in the L-dialcodes file
and prepend the phone number in L.sys with the appropriate
"dialcode" (this hack is needed, because our uucico refuses to
use phonenumbers with letters in L.sys, using the dialcodes
file one can get around that).

Hope this helps,
	Ted.
-- 
| Ted Lindgreen                           ...!mcvax!gouldnl!ted |
| Gould European Unix Support Centre             ted@gouldnl.nl |
| Maarssenbroek, The Netherlands     (USA) ...!gould!tlindgreen |