Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!ncar!gatech!usenet.ins.cwru.edu!ncoast!allbery
From: allbery@NCoast.ORG (Brandon S. Allbery KB8JRR/AA)
Newsgroups: comp.sys.amiga.datacomm
Subject: Re: 19200bps
Message-ID: <1991May7.001557.23299@NCoast.ORG>
Date: 7 May 91 00:15:57 GMT
References: <1991May5.201708.452@cec1.wustl.edu> <1492@caslon.cs.arizona.edu> <1187@uqcspe.cs.uq.oz.au>
Reply-To: allbery@ncoast.ORG (Brandon S. Allbery KB8JRR/AA)
Followup-To: comp.sys.amiga.datacomm
Organization: North Coast Public Access Un*x (ncoast)
Lines: 42

As quoted from <1187@uqcspe.cs.uq.oz.au> by muzzle@cs.uq.oz.au (Murray Chapman):
+---------------
| Hang on! Doesn't the TrailBlazer modem do 19200 baud????
+---------------

The Trailblazer gets 18400 baud using compression; the maximum uncompressed
rate is 10600 baud.  Unidirectional; it has to turn the line around to send
data the other way, which is why the TB has the various "spoofing" modes in
it.

+---------------
| heard a rumour that a TrailBlazer GUARANTEES 100% data transmission, even
| to the point of faking "OK" messages.  One catch: you need a TrailBlazer at
| each end of the connection. :-) ))
+---------------

Depends on what you mean by "faking 'OK' messages".

Telebit spoofing works as follows:  the modem does the protocol (X/Ymodem,
Kermit, or UUCP) to the local computer, but does its own protocol between the
modems.  So it "fakes" ACK packets, but the data *does* go through --- not
even call waiting fazes the Telebit protocol.

+---------------
| I have heard of a case where the radio link to an oil rig was down, and the
| only phone line out to the rig had so much static that voice communication
| was impossible... but the TrailBlazer made it through! (Selecting "good"
| frequency bands).
+---------------

True.  The TB may degrade its speed, but it does so in *small* pieces; it can
drop single carrier frequencies instead of dropping the whole line speed.
I am given to understand that on lines that are so dirty that voice is
impossible, the TB can still do AT LEAST 4800 baud --- if the noise is
confined to certain frequency bands, it can do the full 10800 baud.

++Brandon
-- 
Me: Brandon S. Allbery			  Ham: KB8JRR/AA  10m,6m,2m,220,440,1.2
Internet: allbery@NCoast.ORG		       (restricted HF at present)
Delphi: ALLBERY				 AMPR: kb8jrr.AmPR.ORG [44.70.4.88]
uunet!usenet.ins.cwru.edu!ncoast!allbery       KB8JRR @ WA8BXN.OH