The MSM6895/MSM6896, developed especially for low-power and multi-function applications in ISDN telephone terminals, are single +5 V power supply CODEC LSI devices. The devices consist of the analog speech paths directly connectable to a handset, the calling circuit directly connectable to a piezosounder, the push-button key scanning interface between push buttons and control processors, the dial tone generator, the B-channel interface, the CODEC, and the processor interface. The functions can be controlled via the 8-bit data bus.