I need to restrict the outbound calls to an SPA3000. Is there a way of marking a gateway to only allow one call at a time?

Or, as the SPA3000 registers with FS, allowing the extension to only allow one outbound call. (Problem here is I have not worked out how to send a call to the FXS using the extension information, I have just been sending it as sofia/internal/$1@10.0.0.17:5061 )

If I do this  <action application="bridge" data="user/Line_9@${domain_name}"/>
I get a dial tone, but I can't figure how to send the number in this case.

Obviously my understanding of dial plans is less than what it could be!

This is all necessary, as if you send a second outbound call to the SPA3000, it will then think that there is an inbound call 1min 30 seconds later.

Scott