DESCRIPTION
An intelligent, half-duplex, FFSK/MSK modem which operates under “C-BUS” control. In addition this modem provides software selectable checksum generation and error checking, in accordance with MPT1327. (a) Accept from the host and transmit, 8-bit bytes of data as instructed (Preamble, Sync, Address and data). (b) internally calculate and insert a 2 byte checksum based upon the preceeding 6 bytes of data, or (c) disable the internal checksum generator and continuously transmit the data supplied. 2. Transmit 1 hang-bit and go to Tx Idle when all loaded data bytes have been transmitted. In Rx mode the FX809 will: 1. Detect and achieve bit synchronization within 16 bits. 2. (a) Search and detect the user-programmed Sync (or its opposite logic sense) Word and achieve frame sychronization. Data will then be output in 8-bit bytes via the Rx Data Buffer. Publication D/809/5 April 1998 (b) Use the received checksum to calculate the presence of any errors, setting the Status Register accordingly.
CML
