For line keys:
For SIP-T48G IP phones:
The default value of the line key 1-16 is 15, and
the default value of the line key 17-29 is 0.
For SIP-T46G/T29G IP phones:
The default value of the line key 1-16 is 15, and
the default value of the line key 17-27 is 0.
For SIP-T42G IP phones:
The default value of the line key 1-12 is 15, and
the default value of the line key 13-15 is 0.
For SIP-T41P IP phones:
The default value of the line key 1-6 is 15, and
the default value of the line key 7-15 is 0.
For SIP-T27P IP phones:
The default value of the line key 1-6 is 15, and
the default value of the line key 7-21 is 0.
For SIP-T23P/T23G/T21(P) E2 IP phones: