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 85 (Local Favorite).
When X=9, the default value is 33 (Status).
When X=13, the default value is 0 (NA).
For ext keys:
For SIP-T54S/T52S IP phones:
When Y=1-60, the default value is 0 (NA).
For SIP-T48G/T48S/T46G/T46S IP phones:
When Y=1-40, the default value is 0 (NA).
For SIP-T29G/T27P/T27G IP phones:
When Y=1, 21, the default value is 37 (Switch).
When Y=2-20, 22-40, the default value is 0 (NA).