dialTBIT and T2500 Puzzle

[Dave Hughes]

We are setting up a Telebit T2500 using SCO Unix 3.2.2 and the dialTBIT 
program that SCO provided with the release. (Which won't even compile on the
SCO Unix system unless I comment out the 'nap' lines). We are trying
to use the T2500, UUCP link to T2500s at Colorado Supernet (csn.org)
running on Suns, for UUCP, netmail, and eventually B-news. 

We have examined and tried many combinations of Tbit register settings,
dialTBIT MDSETUP initialization strings from four different sources
(Tbit manual, SCO dialTBIT code, Nutshell, and csn suggested settings
but nothing works, and there are a host of contradictions between these
documents.)

1. The modem is not locking the speed at 19200 but instead allowing it to
   drop to 9600.  Is there a way to keep the modem from rotating down and
   connecting except at 19200?  I've tried the S51 and S66 settings and they
   don't seem to do it.

2. When I do get a connect at 9600, in UUCP the Tbit is not passing the
   information on to the Systems file causing it to never send the login
   name, password, etc.  The Systems file entry works fine at 9600 baud, and
   has for several months using a Robotics dual standard V32 at our end,
   and the SCO release dialHA24 with the modem speed in the code simply
   set to and compiled as dialHA96. So it has to be something with the
   Tbit and the dialTBIT dialer.

Incidentally, I'm calling into Colorado SuperNet so if anybody has a telebit
connection with them and was willing to share it would reduce the possibility
of them needing something special.

Below is a table showing the differences in the settings recommended by
csn, sco (dialer program strings), nutshell, and the T2500 manual, and
what we last tried to use.

All settings not listed are the default T2500 settings.

     CSN      SCO       NUTSHELL       T2500         What we last tried
     V0        V1          -             V1                 V1
     E0        E0          E0            E1                 E0
     X0        X3          -             X1                 X3
     -         F1          -             F1                 F1
     Q0        Q4          Q4            Q0                 Q4
S7   65        -           -             40                S7=40
S10 254        -           -              7                S10=30
S48  -         1           -              0                S48=0
S51 254       254         254           255                S51=254
S52  2         2           2             0                 S51=2
S54  3         3           3             0                 S54=3
S55  -         0           3             0                 S55=0
S58  -         2           2             3                 S58=2
S64  -         -           1             0                 S64=1
S66  1         0           -             0                 S66=0
S68  -        255          3            255                S68=255
S92  1         1           -             0                 S92=1
S110 -        255          -            255                S110=255
S111 -        255          30           255                S111=30
S130 1         -           2             2                 S130=2
S131 1         -           2             2                 S131=2

With some settings we have been able to connect to csn T2500s at
19,200 via cu, but the same settings cause the dialTBIT to abort
when it runs against our T2500 .

So what  do we do to cut through this Gordian Knot?
--------------------------------------------
jonr%bigsky at csn.org
dave%oldcolo at csn.org