# Specifying the Q.SIG node address

If you are building a Q.SIG application using supplementary services, you must specify the address of the Q.SIG node when your application starts the stack. To do so, specify the address number and type in the ISDN_PROTOCOL_PARMS_Q931CC structure referenced in the isdnStartProtocol call. The following fields specify the address:

- qsig_source_type_of_nb

- qsig_source_party_nb_type

- qsig_source_addr

For more information about these fields, including a list of possible values, see the NMS ISDN Messaging API Developer's Reference Manual.