For the memory key and programable key, the
default value is not applicable.
For the line key, when x=1, the default value is 1.
When x=2, the default value is 2.
…
When x=6, the default value is 6.
Configures the value for some key features.
For the memory key, x ranges from 1 to 10.
For the line key, x ranges from 1 to 6.
For the programable key, x ranges from 1 to 14
(For SIP-T19P IP phones, x=1-9, 13, 14; For
SIP-T20P IP phones, x=5-12, 14; For SIP-T21P IP
phones, x=1-10, 14; For SIP-T22P IP phones,
x=1-10, 12-14; For SIP-T26P/T28P IP phones, x
ranges from 1 to 14).