Проблема с pppd

кусок лога:

Aug 17 18:09:49 [pppd] pppd 2.4.2 started by root, uid 0
Aug 17 18:09:49 [pppd] Using interface ppp0
Aug 17 18:09:49 [pppd] Connect: ppp0 <--> /dev/ttyLT0
Aug 17 18:10:19 [pppd] LCP: timeout sending Config-Requests_
Aug 17 18:10:19 [pppd] Connection terminated.
Aug 17 18:10:19 [pppd] Receive serial link is not 8-bit clean:
Aug 17 18:10:19 [pppd] Problem: all had bit 7 set to 0
Aug 17 18:10:19 [pppd] Exit.

коннект не устанавливается, помогите советом, куда копать ? из за этого не работают chestnut-dialer и wvdialer