5.1  Yaesu older 5-byte command radios

Modern Yaesu radios transmit and receive CAT data in the form of readable ascii text.

eg:   FA145500000;


Kenwood and Elekraft use a similar system  (Many Kenwood codes are the same as Yaesu)


In piWebCAT the configuration for these radios is selected in the rigs table as ASCII.
The ASCII configuration system is described in detail earlier in this document.

It uses masks where selected lower case letters map to the data within the command.
All other mask characters are included in the command verbatim.


Earlier Yaesu radios used CAT data constructed of hexadecimal and binary coded decimal bytes.

All commands to the radio are 5 bytes. Returned data packets from the radio can be from 1 to 32 bytes.

These radios include: FT847, FT817, FT818, FT920, FT890, FT1000, FT1000MP mkv.


Unlike the modern text configured radios, they do not have matching pairs of read and write commands.

Setting and reading commands are completely separate and differently structured.

For example:

  • FTdx101D  -  RF power:   Set  95w is  PL095;   Read is PL; with answer  PL095;
  • FT920  -    A relatively limited range of setting commands  - no RF power setting.
                   Received data:   Status updates: eg:  28 byte VFO A and B freq, mode, clarifier block.
                                   Status flags - returns 8 bytes with a variety of bitwise information.
                                   Read meter: returns S-meter. power  etc
                                                          - but also NR, PROC and squelch levels (NO CAT setting of these)

I have had an FT847 for many years.

This has a very limited set of CAT commands  ... including  switching of the unique satellite features.

I used this to develop a configuration system for the 'five byte' system.

The FT818 is similar but with a few extra commands.

I had some help in testing from a FT818 owner during development and so my supplied database
contains an FT818 configuration.


I then acquired an FT920 and developed a configuration database for it.
The FT920 has a much larger set of commands and so my supplied FT920 database provides a
good starting point for a user to configure for FT1000 etc.


The YAESU5 configuration option

The configuration is selected in the rigs table as:   YAESU5.

It uses the same tables as the ASCII configurations.   
The user enters commands in fields: readmask, setmask and answermask as text characters.

The outgoing read and set commands to the radio are configured as ten characters in readmask and setmask.

The RPi web server translates the ten characters to five bytes for transmission to the radio.


answermask is dealt with differently. (otherwise, a mask of 56 characters would be required to decode 28 bytes)


answermask configuration text is of the form  #08:03:01:1Fbb

      = receive 08 bytes. Extract 01 byte starting at byte 3. Perform a logical AND with hex 1F to return bits 0 - 4.

(This is discussed in detail and with examples later)


The system allows the use of easily interpreted text to configure a somewhat more complex CAT system.


The five byte outgoing commands are the easiest to deal with:

eg: FT847 read frequency and mode is: specified as five bytes:  *  *  *  *  E7    where * are  don't care bytes.

So I entered readmask = 00000000E7 as text

The server converts this to hexadecimal bytes:  00  00  00  00  0xE7