wvdial Time Out

[wilcut...@gmail.com]

I'm using wvdial to keep a USB 3G modem online.  When I bring up the modem, it stays up for 25 minutes'ish while I can ping it.  Suddenly pings stop.  After a fair amount of experimenting, it seems the connection lasts for almost exactly 25 minutes each time before something disconnects.

If I restart wvdial, everything goes back to normal... for 25 minutes.

My /etc/wvdial.conf file:

[Dialer Defaults]
Idle Seconds = 0
Init1 = ATZ
Init2 = ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0
Modem Type = Analog Modem
Baud = 9600
Phone = #777
Modem = /dev/ttyUSB0
ISDN = 0
Stupid Mode = 1
Username = <removed for this post>
Password = <removed for this post>
New PPPD = yes
Auto Reconnect = on
Idle Seconds = 0

When I looked through the wvdial source code, there didn't seem to be anything there to suggest a 25 minute timeout issue.   Has anyone had this issue?  Any ideas?

Thanks!