You can take a specified channel or an entire PRI interface out of service or put it into one of the other states that is passed in to the switch. To do so, complete the following task in interface configuration mode:
"AS5350(config-controller)# isdn service dsl number b_channel 0 state state-value"---- Sets the entire PRI interface to the specified state.
Refer the following link for more information on blocking T1 circuits in AS5400: