HD81805

The HD81805 is a kind of CMOS single-chip digital signal processing LSI which has 4 channels pushbutton (DTMF)/dial tone (DT) receiver for PABX, center and terminal. Each 4 terminal is selected DTMF or DT receiver by command independently. Current analog systems can be replaced to full digital systems with smoller board size and lower price by this HD81805.

There are some features of HD81805 as follows: (1)high reliability by full digital signal processing; (2)4 channels pushbutton (DTMF)/dial tone (DT) receiver selected independently; (3)center to end mode/end to end mode (EE); (4)operating characteristics parameters (operation signal levels, signal reception timing, and so on) are programmable; (5)2 type of output data logic format; (6)early steering flag is supported; (7)serial interface for connecting to A-law/-law PCM CODEC directly; (9)8-bit microcomputer interface for parallel data input.

The last one is about the functional summary of HD81805: (1)sampling frequency: 8 kHz; (2)input data format: 8-bit A-law/-law PCM CODEC data format; (3)serial interface (CODEC): connected to A-law/-law PCM CODEC directly; (4)parallel interface (MPU): 8 bit MPU; (5)process: CMOS 1.3m; (6)power dissipation, 150 mW typ (unloaded output); (7)power supply voltage: +5 V±5%.