PC XMODEM Async comm to AS/400

I'm hoping someone out there has an answer to this.  It's probably not
that complicated, but if anyone has already done this, knows someone who
has, or knows of an available software comm solution that can be
purchased to do this, I would appreciate knowing.

Present application (distributed at over 200 locations) has a PC DOS
based application that dials up to a Unix box and using Async XMODEM 
comm uploads flat files.  An AS/400 then runs a regular job that does
SLIP TCP dial to the Unix box and FTP's any new data back to the 400 for
processing.  The PC application can't really be changed (so having them
do a SLIP TCP dialup to the 400 and FTP the file directly is out) due to
the problems of getting it distributed to all required sites (half of
which have 386 or older PC's) - but what we would like to do is
eliminate the Unix box and have the PC's call the 400 directly and
upload the data.
It would have to handle the communications from the PC without changing
the PC application.

Any ideas ?

TIA

-- 
...Neil Palmer                                      AS/400~~~~~      
...AS/400 Technical Specialist      ____________          ___  ~     
...NxTrend Technology - Canada      |OOOOOOOOOO| ________  o|__||=   
...Markham,  Ontario,   Canada      |__________|_|______|_|______)   
...Phone: (905) 731-9000  x238       oo      oo   oo  oo   OOOo=o\   
...mailto:npalmer@nxtrend.com    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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