Pls confirm if IP Phone 521SG can be registered to CUCM-5.1.2 or if its having limitation to be registered with CUC 500series only.
These models will not work with and current CUCM Version :(
Q. What is the CiscoÂ® Unified IP Phone 500 Series?
A. The Cisco Unified IP Phone 500 Series is a group of cost-effective, entry-level phones designed to work ***solely with the Cisco Unified Communications 500 Series for Small Business.
Hardware Features and Enhancements
The Cisco 500 Series phones offer customers the option of having a 10/100 switch port for connecting to a co-located PC via a LAN connection, if needed. The Cisco Unified IP Phones 521SG and 524SG offer the 10/100 switch port, while the 521G and 524G models do not. Orderable now.
***These phones are designed for use with the Cisco Unified Communications 500 Series for Small Business only. They will not work with any other Cisco platform.
Hope this helps!