Why would you want to. A bell is a type of signalling just use more than 1 and better signalling. The bell usnt what deters intruders its the fear of getting caught. If Noone hears the bell Noone will respond etc etc
I would always use a tx. Had a situation recently when an arc denied they had any alarms from a site after a fuel theft. The adpro log proved there was alarms and images sent etc.
no you need to assign an address it may not keep its address if you disable dhcp. Also if you do disable it on the router then other devices wont work unless they are assigned a static ip manually