Unfortunately at this time the SPA500DS is not supported on UC540/UC560, only the SPA500S. The SPA500DS is only supported in SIP mode.
Based on the Session Initiation Protocol (SIP), the Cisco SPA500DS has been tested to ensure comprehensive interoperability with equipment from voice over IP (VoIP) infrastructure leaders, enabling service providers to offer competitive, feature-rich services to their customers.
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...