The CMX612 is a low power CMOS integrated circuit for the reception of physical layer signals used in British Telecom's Calling Line Identification Service (CLIP), Bellcore's Calling Identity Delivery system (CID), the Cable Communications Association's Caller Display Services (CDS) and similar evolving systems. It also meets the requirements of emerging Caller Identity with Call Waiting services (CIDCW). In addition, it provides Visual Message Waiting Indicator (VMWI) detection in both CLASS (FSK) and (SDT) Stuttered Dial Tone modes. Two different signal inputs are provided to the device, to support Tip/Ring and Hybrid connectivity. The device includes a `zero-power' ring or line reversal detector, a dual-tone (2130Hz plus 2750Hz) Tone Alert Signal detector, a dual-tone (350Hz plus 440Hz) stuttered dial tone detector and a 1200-baud FSK V23/Bell202 compatible asynchronous data demodulator with a data retiming circuit which removes the need for a UART in the associated Controller. It is suitable for use in systems to BT specifications SIN227 and SIN242, Bellcore GR-30-CORE and SRTSV-002476, CCA TW/P&E/312, ETSI ETS 300 659 parts 1 and 2, ETS 300 778 parts 1 and 2 and Mercury Communications MNR 19.