This is a modem config question, and since you didn't indicate what
brand modem you have, I can only make a guess. However, typically
the &D value decides what a modem does on disconnect. Check your
modem manual for this. Anyway, on many modems &D2 will cause the
modem to do a "hard reset" on disconnect. On others the value is &D3.
On still others it's controlled by an S register.
-- Bri