The procedure to lock and unlock configuration mode for Cisco Session Initiation Protocol (SIP) IP phones changes, starting with SIP IP phone software version 4.2.
For information on these procedures for both versions 4.2 or later and 4.1 or earlier, refer to these documents:
Note: The default phone_password discussed is "cisco". This can be modified in the SIPDefault.cnf and SIPMACaddr.cnf files if needed. For more information, refer to the Modifying the SIP Settings section of the document.
For information on the unlocking and locking procedure for non-SIP IP phones, refer to the Unlocking and Locking Configuration Options section of Cisco IP Phone Model 7960G and 7940G Administration Guide for Cisco CallManager Release 4.1: An Overview of the Cisco IP Phone.