Call restriction feature is planned for a future release.
There is a workaround available for current release. If you configure the system as Key System (instead of blend or PBX), you can place a phone without keys (i.e. SPA301 or SPA502) in a public area. These phones will get an extension but will not be able to dial out as they dont have trunk keys.
Configure Multicast Paging on the Cisco IP Phone 7800 Series or 8800 Series Multiplatform Phone
The Cisco IP Phone 7800 and 8800 Series Multiplatform Phones provide voice communication over an Internet Protocol (IP) network...
Add Call Park on a Cisco 7800 or 8800 Series Multiplatform Phone Key Expansion Module
Call park allows the user of the phone to put an incoming call on hold so that the call can be retrieved on another phone. A call is park...