Yealink SIP-T2 SERIES Administrator's Manual page 971

Appendix
When X=2, the default value is 61 (Directory).
When X=3, the default value is 5 (DND).
When X=4, the default value is 30 (Menu).
When X=5, the default value is 28 (History).
When X=6, the default value is 61 (Directory).
When X=7, the default value is 0 (NA).
When X=8, the default value is 0 (NA).
When X=9, the default value is 33 (Status).
When X=10, the default value is 0 (NA).
When X=14, the default value is 2 (Forward).
For SIP-T19(P) E2 IP phones:
When X=1, the default value is 28 (History).
When X=2, the default value is 61 (Directory).
When X=3, the default value is 5 (DND).
When X=4, the default value is 30 (Menu).
When X=5, the default value is 28 (History).
When X=6, the default value is 61 (Directory).
When X=7, the default value is 0 (NA).
When X=8, the default value is 0 (NA).
When X=9, the default value is 33 (Status).
When X=13, the default value is 0 (NA).
When X=14, the default value is 2 (Forward).
For CP860 IP phones:
When X=1, the default value is 28 (History).
When X=2, the default value is 61 (Directory).
When X=3, the default value is 5 (DND).
When X=4, the default value is 30 (Menu).
When X=5, the default value is 28 (History).
When X=6, the default value is 61 (Directory).
When X=9, the default value is 33 (Status).
When X=13, the default value is 0 (NA).
For ext keys:
For SIP-T48G/T46G/T29G/T27P IP phones:
The default value of the ext key 1, 21 is 37, and
the default value of the ext key 2-20, 22-40 is 0.
Valid values are:
Range
0-N/A
949