Simon Collings - RS-232 Interfacing for Receiver Control

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RS-232 Control of the Yaesu FRG-8800

Interface Unit: FIF-232C (converts 5V TTL to RS-232 polar)

Standard Connections Used: TXD, RXD, GND

Flow Control: None (for the equipment featured here)

Type of RS-232 Command Set: Binary, 5-byte fixed length frames (1-byte opcode + 4bytes of data/parameters)

Data Parameters: 4800 bps (fixed), 1 start, 8 data + 2 stop bits

FRG-8800 Interface

The format of command data frames is the same as for the FRG-100 (sent left to right) as follows:

1	2	3	4	5
4th Arg	3rd Arg	2nd Arg	1st Arg	Opcode

The FRG-8800 supports more commands that the FRG-9600, but still does not include an s-meter read command. You will notice that there are subtle differences in the structure of the command frame compared with the FRG-100 (as with the FRG-9600) and that none of the receivers are mutually compatible.

Function

Opcode
(hex)

Arg1

Arg2

Arg3

Arg4

Argument description

Set Operating
Frequency

0ah

New operating frequency in BCD format:
Example: To set 14.250MHz the values of
f1-f4 are:

f1	00h
f2	50h
f3	42h
f4	01h

(note: lsb of f1 defines number of 25Hz increments as follows: 1=0Hz, 2=25Hz, 4=50Hz, 8=75Hz)

Mode

80h

Select mode as follows:

m	mode
00h	AM-W
08h	AM-N
01h	LSB
02h	USB
03h	CW-W
0bh	CW-N
04h	FM-W
0ch	FM-N

External RS-232 Control

00h

ext

ext=00h (on) or ext=80h (off)

Tape

80h

t=feh (tape relay on), t=ffh (tape relay off)