Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!swrinde!kent
From: kent@swrinde.nde.swri.edu (Kent D. Polk)
Newsgroups: comp.sys.amiga
Subject: Re: Dnet
Keywords: Dnet, Telebit Trailblazer
Message-ID: <25373@swrinde.nde.swri.edu>
Date: 7 Mar 90 22:17:44 GMT
References: <25358@swrinde.nde.swri.edu> <1990Mar7.000117.6984@ncsuvx.ncsu.edu>
Reply-To: kent@swrinde.UUCP (Kent D. Polk)
Distribution: na
Organization: Southwest Research Institute, San Antonio, Texas
Lines: 38

In article <1990Mar7.000117.6984@ncsuvx.ncsu.edu> ml@ecerl3.UUCP () writes:
>In a previous article, kent@swrinde.nde.swri.edu (Kent D. Polk) wrote:
>
>]Also, I have been loaned an Telebit Trailblaser for a while & tried to
>]run Dnet in the PEP (19200) mode, but severe thrashing between Dnet and
>
>I think that this particular problem lies outside of DNET.  I also got
>ahold of a trailblazer for awhile, and ran into the same difficulties.
>I was just using terminal emulators doing file transfers (typically
>Zmodem in JRCOMM, various protocols in other things like Handshake or
>VT100) and I found that my throughput always seemed to be around 600
>cps (about 570 actually).  JRCOMM's info window showed that packets were
>continuously being resent (about 1 in every 4 or 5 packets) ... I strongly
>suspect that this IS some sort of handshaking problem.

Handshake can be a big problem above 2400 baud. I found that with
normal term. programs, RTS/CTS works the best. Actually, as I mentioned
in my original posting, I can get DNET to work fine at 2400 with the
Trailblazer. The higher speeds are the problem.

>I also did a lot of experimenting with handshaking options, to no avail.
>The proper way to configure this beastie should be to enable hardware 
>handshaking (CTS,RTS).  I turned CTS/RTS handshaking on via Preferences, 
>inside my terminal program, and within the modem (setting some register).
>Nothing seem to help (let me know if you have answers!).  

This works fine for those programs which don't go and turn off RTS/CTS.
Running Xmodem with the Trailblazer in xmodem protocol at 19200 really
rips when you have a term program which can pull it in fast enough :^)

>The modem does all sorts of data compression techniques to get its speed.

Actually, it gets it's speed by using up to 512 different frequencies,
not so much by using data compression (the statistics reports on
frequencies used, etc. are pretty neat). The MNP protocol is the one
which uses data compression to get the higher speeds from what I
remember (little do I know). PEP can make use of data compression, but
does not require it for the faster speeds.