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From: tempest@wet.UUCP (Ken Lui)
Newsgroups: comp.dcom.modems,comp.sys.ibm.pc,comp.sys.mac
Subject: Telebit Trailblazers' undocumented registers
Keywords: Telebit registers
Message-ID: <894@wet.UUCP>
Date: 31 Dec 89 07:05:47 GMT
Followup-To: poster
Organization: Wetware Diversions, San Francisco
Lines: 30

I just read a message on a Fidonet board and someone posted a
message to the effect that setting register 120 to a value of 12
on a T2500, or any Trailblazer, would result in better
performance.  I looked in my T2500 manual and it made no mention
of an S120.  In fact, doing a register dump--atn?--in extended
command mode doesn't even show S120.

I tried to set it anyway, and my modem responded with an OK.
Hmmm, what's going on here?  I did another atn? and lo and
behold, S120 showed up as S120:12.  Setting it back to 0 made it
"invisible" again.  I then tried to set S113 to some value and my
modem spitted back OK; however, an atn? doesn't list it among the
registers.  Usually, referencing an invalid register results in
an ERROR message.

Are there undocumented registers in the Telebit Trailblazers?
Incidentally, I followed that PEP thread and somebody else
commented that S120 was used to eliminate micro-packets.  Any
insights with respect to this would be greatly appreciated.

Ken
p.s. I'd like to thank everyone who responded to my previous post
     requesting a source for a Telebit T2500.  If anybody wants 
     the responses, I'll gladly send them via netmail, or post
     them to these groups.
-- 
_____________________________________________________________________________
     Kenneth K.F. Lui	   |  UUCP:	...{ucsfcca|claris}!wet!tempest
     tempest@wet.UUCP	   |  Internet:	cca.ucsf.edu!wet!tempest@cgl.ucsf.edu
			   |	-or- 	claris!wet!tempest@ames.arc.nasa.gov