Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!lll-winken!ames!pacbell!hoptoad!peora!rtmvax!bilver!jwt!john
From: john@jwt.UUCP (John Temples)
Newsgroups: comp.dcom.modems
Subject: Hacking the Trailblazer (was: Re: hi speed modems in Germany)
Message-ID: <131@jwt.UUCP>
Date: 1 Apr 89 21:47:00 GMT
References: <729@impch.UUCP> <564@ispi.UUCP>
Reply-To: john@jwt.UUCP (John Temples)
Organization: John W. Temples, III -- Orlando, FL
Lines: 27

In article <564@ispi.UUCP> jbayer@ispi.UUCP (Jonathan Bayer) writes:
>In article <729@impch.UUCP> patg@impch.UUCP (Patrick Guelat) writes:
>>
>>I think there is an undocumented register in v4.0 of the firmware ...
>>Perhaps telebit can answer this and tell us if there are other
>>undocumented registers.
>
>[ description of undocumented S120 ]

I had a problem with my TB+ making an MNP connection to CompuServe at 2400
bps.  Telebit told me to set the undocumented S39 register to 3 in order to
disable MNP Class 4 features.  This worked fine, and I can now connect to
CompuServe with MNP Class 3.  After hearing about S120 and S36 on the net,
and S39 from Telebit, I decide to play around with my Trailblazer a bit.  I
found a couple more undocumented features.  ATJ6 enables debug mode, required
to modify undocumented debug registers and to issue other J commands.  J4
displays the elapsed time of the current connection.  J5 puts you into an
interactive debugger of some sort.  Within the debugger, "M" lets you modify
addresses (I think), "N" prints dots until you turn the modem off, and "T"
exits the debugger.  J0 prints out some information of meaning unknown to me.
J1 prints out "099".  J2, J3, and J7 return "OK", but I don't know what they
do.

Has anyone else discovered any interesting "undocumented" features in the
Trailblazer?
-- 
John Temples - UUCP: {uiucuxc,hoptoad,petsd}!peora!rtmvax!bilver!jwt!john