asterisk users - Oct 2005 - Zaptel Debug: "T1: Lost our place, resyncing "

We are trying to debug a connection between Asterisk and a legacy PBX (Mitel
SX200). We turned on the Zaptel debugging and we get the following message
quite frequently:

Oct 12 07:14:09 localhost kernel: T1: Lost our place, resyncing ( 28 )
Oct 12 07:14:09 localhost last message repeated 3 times
--
Oct 12 07:14:11 localhost kernel: T1: Lost our place, resyncing ( 28 )
Oct 12 07:14:11 localhost last message repeated 7 times
--
Oct 12 07:14:15 localhost kernel: T1: Lost our place, resyncing ( 28 )
Oct 12 07:14:15 localhost last message repeated 5 times
--
Oct 12 07:14:17 localhost kernel: T1: Lost our place, resyncing ( 28 )
Oct 12 07:14:17 localhost last message repeated 7 times
--
Oct 12 07:14:26 localhost kernel: T1: Lost our place, resyncing ( 28 )
Oct 12 07:14:26 localhost last message repeated 5 times
--
Oct 12 07:14:28 localhost kernel: T1: Lost our place, resyncing ( 28 )
Oct 12 07:14:28 localhost last message repeated 6 times
--
Oct 12 07:14:33 localhost kernel: T1: Lost our place, resyncing ( 28 )
Oct 12 07:14:33 localhost last message repeated 5 times
--
Oct 12 07:14:33 localhost kernel: T1: Lost our place, resyncing ( 28 )
Oct 12 07:14:33 localhost last message repeated 7 times
--

What does this log entry mean?

We are using a Digium TE110P connecting via T1 crossover cable to a Mitel
SX200 T1 Card.  Our connection just recently began producing enough slip and
frame errors to cause the Mitel to automatically take it's T1 card offline.
Since we just started with the debugging, we're not sure if we would have
had these entries when the system was operational.

We are using an identical server/TE110P integrating with an IsoTec Executone
and we do not receive those log entries.

Thanks,
Geoff