I am trying to configure 525G with CME version 7.1. I tried both SCCP and SIP, and it's not being register to CME. Is 525G supported by CME though?
The 500 series IP Phones are only supported with the
Small Business UC500 (520,540,560). They are not
supported on CME.
This section below does not mention the 525G (As it is an older doc) but the restrictions do carry across;
The Cisco Unified IP Phones 521G, 524G, 521SG, and 524SG address the communication needs of any Cisco Smart Business Communications System (SBCS) implementation. These phones are designed to work ***solely with the Cisco Unified Communications 500 Series for Small Business.
Cisco Unified CME 7.1 Supported Firmware, Platforms, Memory, and Voice Products
Hope this helps!