Yaesu FT-817 Operating Manual

Also see for FT-817 -: Brochure & specs Operating manual Technical supplement Manual Modification Instructions

71FT-817 Operating ManualCAT S YSTEM P ROGRAMMINGCAT Data ProtocolAll commands sent from the computer to the transceiver consist of five-byte blocks, with upto 200 ms between each byte. The last byte in each block is the instruction opcode, while thefirst four bytes of each block are arguments (either parameters for that instruction, or dummyvalues required to pad the block out to five bytes). Each byte consists of 1 start bit, 8 databits, no parity bit, and two stop bits.There are 17 instruction opcodes for the FT-817, listed in the chart on next page. Many ofthese opcodes are On/Off toggle commands for the same action (e.g. “PTT On” and “PTTOff.” Most of these commands require some parameter or parameters to be set. Irrespectiveof the number of parameters present, every Command Block sent must consist of five bytes.Accordingly, any CAT control program must construct the five-byte block by selecting theappropriate instruction opcode, organizing the parameters as needed, and providing unused“dummy” Eargument bytes to pad the block to its required five-byte length (the dummybytes can contain any value). The resulting five bytes are then sent, opcode last, from thecomputer to the FT-817 CPU via the computer’s serial port and the transceiver’s ACC jack.All CAT data values are hexadecimal.Constructing and Sending CAT CommandsExample #1: Set the VFO frequency to 439.70 MHz Per the CAT command table, the opcode for “Set Frequency” is 01. Placing the opcodeinto the 5th data bit position, we then enter the frequency into the first four data bitpositions:DATA 1 DATA 2 DATA 3 DATA 4 DATA 5 43 97 00 00 01Parameter CommandSend these five bytes to the transceiver, in the order shown above.Example #2: Turn the Split Mode “On” Per the CAT command table, the opcode for “Split On/off” is 02. Placing the opcodeinto the 5th data bit position, we then enter dummy values into all other parameter loca-tions:DATA 1 DATA 2 DATA 3 DATA 4 DATA 5 00 00 00 00 02Dummy Data Command CAT DATA BYTE FORMAT CAT 5-BYTE COMMAND STRUCTURE