HT95LXXX
DTMF frequency selection table: register DTMFD[21H]
Low Group
High Group
DTMF Output
DTMF
Code
TR4
0
TR3
0
TR2
0
TR1
1
TC4
0
TC3
0
TC2
TC1
1
Low
697
697
697
697
770
770
770
770
852
852
852
852
941
941
941
941
High
1209
1336
1477
1633
1209
1336
1477
1633
1209
1336
1477
1633
1209
1336
1477
1633
0
1
0
0
0
1
0
0
0
1
0
0
0
1
0
0
1
2
3
A
4
5
6
B
7
8
9
C
*
0
0
0
1
0
0
0
0
0
0
1
0
1
0
0
0
0
1
1
0
0
0
0
1
0
0
0
1
0
0
1
0
0
0
0
0
0
1
0
0
1
0
0
0
1
0
1
0
0
0
1
0
0
0
0
1
0
1
0
0
0
0
0
0
1
0
0
0
1
0
0
1
0
0
1
0
0
1
0
0
0
0
0
1
1
0
0
0
0
0
0
0
#
D
1
0
0
0
0
1
0
1
0
0
0
1
0
0
Single tone for testing only
0
0
0
1
0
0
0
0
0
0
1
0
0
0
0
0
0
1
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
1
0
0
0
0
0
0
1
0
0
0
0
0
0
1
0
0
0
697
770
852
941
1209
1336
1477
1633
Writing other values to TR4~TR1, TC4~TC1 may generate an unpredictable tone.
Rev. 1.20
24
May 26, 2004