Apple Geoport V.34 interoperability problem

[Russell J Dwarshuis]

There is a problem with Apple Geoport Telecom adapters using 3.0 software
connecting to General DataComm modems when using V.34.  Users may see slow
connect speeds, long pauses during data transmission, and may be abruptly
disconnected after a minute or so.  The Geoport does not show this problem
when dialing into U.S. Robotics modems. 

GDC has started to look into the problem.  For now, the only work around 
is to disable V.34 on the Geoport by setting s-register 110 to 1 (using 
the command ats110=1).  This forces the modem to use V.32bis instead.

The Geoport is a device which relies on the CPU on the Apple computer for
much of the computation which is ordinarily done on specialized hardware
in a stand-alone modem.  I verified this problem on a Power Macintosh 
7200/120.  Faster machines may not have this problem.

                                            
                                            -Russell Dwarshuis
                                             Engineer, Merit/MichNet

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