At what stage do these calls drop? During trainup or during the PPP phase or after a few minutes after connecting?
We need to see the outputs such as modem call record terse / show modem log x/y / sh modem op x/y to determine the disconnect cause.
Is the controller clean, show controller t1?
http://www.cisco.com/en/US/tech/tk801/tk36/technologies_tech_note09186a0080094ebd.shtml
Has this problem started offlate or was always there?
Thanks, Mak.