b400p elastix d-span up down event

Hi all,
i have installed b400p card with elastix and dahdi drivers. i tried to use trixbox/elastix with misdn but mr.deng adviced me to install elastix and use dahdi driver (and he gave me a hand to set it up - THANKS). but i have some problem.
our client have 2 isdn box. if i connect box A everything is working fine, but if i check with box B i can call out, but i have non signal on calling in. i checked cables, and i switched with box A's cable.
i am sure that cable is fine. isdn box are the same (model NT1 PLUS 2B1Q).

so i dont know what to check. i tried to set verbosit level 12, but i have no log when i call in.
everything what i have when i connect isdn from box B is:

== Primary D-Channel on span 4 up
== Primary D-Channel on span 4 down
== Primary D-Channel on span 4 up
== Primary D-Channel on span 4 down
== Primary D-Channel on span 4 up
== Primary D-Channel on span 4 down
== Primary D-Channel on span 4 up


all the time


what can i check?

regards
gerards

ISDN box? did you mean isdn modern?