For the 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=3 the default value is 3 
… 
When X=16 the default value is 16. 
Permitted Values: 
1 to 16 (for SIP-T48G/T46G/T29G) 
1 to 12 (for SIP-T42G) 
1 to 6 (for SIP-T41P/T27P) 
1 to 3 (for SIP-T23P/G) 
1 to 2 (for SIP-T21(P) E2) 
1-Line 1 
2-Line 2 
… 
16-Line 16 
Configures the value for some key features. 
For line keys: 
X ranges from 1 to 29 (for SIP-T48G). 
X ranges from 1 to 27 (for SIP-T46G/T29G).