Jaton Modem never responses EXCEPT in Seyon

[Hongyu Lu <hongyulu@cse.Buffalo.EDU>]

I just bought a Jaton Modulator 56K modem and tried to installed it on    
my PC. The problem is that the modem DOES response to the 'dial'
command of Seyon and then dial out, but it never responses to other ppp 
tools like ifup and wvdial(even no response to AT, ATZ commands). I wonder  
if anybody could help me to figure out the possible problems. Thanks for
your kind help.

Hongyu Lu