[asterisk-ss7] problem in mtp2 as sigchannel

[shoieb_arshad]

hello 
i am getting an error when i set mtp2=16 in zaptel .conf

"""""""""""""""""
Changing signalling on channel 16 from Clear channel to MTP2
ZT_CHANCONFIG failed on channel 16: Invalid argument (22)
Did you forget that FXS interfaces are configured with FXO signalling
and that FXO interfaces use FXS signalling?
""""""""""""""""""
can any bosy help me>???????


Muhammad Shoieb Arshad
Department of Electrical Engineering,
Comsats Institute of Information Technology,
Islamabad, Pakistan.
PH # 03006805270