name:         HT9305BI
function:     5-Memory Tone/Pulse Dialer
package:      SKDIP22,22
manufacturer: Holtek

       +--()--+
  HDIB | 1  22| HDO
   C1B | 2  21| R4B
   C2B | 3  20| R3B
   C3B | 4  19| R2B
   C4B | 5  18| R1B
   C5B | 6  17| MODE
    X1 | 7  16| DTMF
    X2 | 8  15| POB
XMUTEB | 9  14| HKSB
   VSS |10  13| VDD
   HFI |11  12| HFO
       +------+


This pinout came from the Chipdir:
http://www.chipdir.org/