How show zap/dahdi channel calling number

i setup a test scenario:

an E1 connection between asterisk and ciscoCallMgr
outgoing trunk is with 9 prefix.
so when sipp(300) call 9400, the call will from trunk to ciscoCallMgr,
and ciscoCallMgr will relay the call backto asterisk to another sipp(400).

sipp====>9400__ ==>400___
\ asterisk/ \ciscoCallMgr
sipp<===400====/ \ ___400<==/

now the problem is call is ok, but when i want to show trunk status:

CallManager*CLI> dahdi show channels
Chan Extension Context Language MOH Interpret
pseudo default default
1 from-pstn default
2 400 from-pstn default

only show called extension number for incoming call,
how can i show the calling number, because i may misunderstand the blank channel is idle, but actually it is occupied by calls.