No DAHDI commands

Hi…

i am used vicidial server with
asterisk version 1.4.39
DAHDI Tools Version - 2.4.1
DAHDI Version: 2.5.0.1
Echo Canceller(s): HWEC, MG2 Configuration
no i can’t find out any dahdi cammands in asterisk cli mode
i got " no such command"
why this error ?

please help me
how can i resolve this error ?

Try module load chan_dahdi.so