Cmterm-7975-sip.9-4-2sr4

Maintenance and stability updates. It is often cited as the final SIP firmware released for the CP-7975G model. Deployment & Compatibility

This firmware is critical for "de-Ciscoing" the phone—converting it from the proprietary Skinny Call Control Protocol (SCCP) to the standard SIP protocol. While the cmterm-7975-sip.9-4-2sr4

: They resolve "memory leak" issues or random reboots that can plague aging hardware. Improve Interoperability Maintenance and stability updates

The file identifier cmterm-7975-sip.9-4-2sr4 denotes a firmware package intended for deployment on Cisco Unified Communications Manager (CUCM). This release enables the Cisco 7975G—a high-end, color-display business IP phone—to operate using the industry-standard SIP protocol rather than Cisco’s proprietary Skinny Client Control Protocol (SCCP). While the : They resolve "memory leak" issues

SIP (Session Initiation Protocol), which is an open-standard protocol used for establishing and managing multimedia communication sessions.