The FX604D4 is an interface modem integrated circuit designed for data communication applications. It supports FSK and V.23 data formats with a baud rate of 1.2k. The FX604D4 operates with a supply voltage range of 3V to 5.5V, ensuring compatibility with various power sources. It is surface mounted with a 16-SOIC package, providing ease of integration into electronic circuits. This interface modem is not suitable for new designs and is an active product from CML Microcircuits, a reputable manufacturer in the industry. It is suitable for applications that require reliable and efficient data communication.