The CH1787 is a small footprint, full function 2400bps, V.22bis asynchronous modem designed to be used in applications where there is little or no external controller intelligence to command the modem. The CH1787 allows the user to operate the modem via hardware resources only, not requiring AT command execution for basic operation. For those applications where an external controller is available, the CH1787 operates like a standard AT Command driven modem.