Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!uwm.edu!ogicse!emory!mephisto!ncsuvx!news
From: ml@ecerl3.ncsu.edu
Newsgroups: comp.sys.amiga
Subject: Re: Dnet
Keywords: Dnet, Telebit Trailblazer
Message-ID: <1990Mar7.000117.6984@ncsuvx.ncsu.edu>
Date: 7 Mar 90 00:01:17 GMT
References: <25358@swrinde.nde.swri.edu>
Reply-To: ml@ecerl3.UUCP ()
Distribution: na
Organization: North Carolina State University
Lines: 39

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
]the Trailblazer occurred.  My effective throughput is about 600 baud in
]PEP mode (needless to say, I went back to 2400 baud). I have tried
]about every combination of setup parameters with Dnet & the
]trailblaser, but none work. At first it appeard to be a handshake
]problem, with dnet maybe loosing characters when the TB spits out a
]burst of chars, but I'm not so sure now.

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.

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!).  

-------------------------------------------------------------

A semi-related question about throughput:

The modem does all sorts of data compression techniques to get its speed.
Protocols like Zmodem also do compression.  
Will the compression done by Zmodem (or "compress" or "arc" or "squeeze"...)
likely *decrease* the transmission rate when using data compression modes
(MNP or PEP) on the modem?  (since applying a compression technique to data
which is already well compressed often yields *worse* results).


             ==[ ml@eceris.ncsu.edu (128.109.135.109) ]==