The original release of FS5000 transceivers had no Digital Control Unit.
I started a project to reverse engineer a very basic unit.
Some more FS5000 have been released in April 2012 which have the DCU, but they only do burst mode.

PROTOTYPE 1
My original prototype was just a connection between a computer parallel printer port and the FS5000 D25 connector. A board was used in between, with LEDs to show the line status. A control program was written in the BASIC language. This enabled the function of the lines to be deteremined, through trial and error. When the primitive functions were discovered, the circuit of a minimal interface board was drawn and the software tidied up.

CONTROL PROGRAM V1
Written in BASIC to run on an IBM PC
Controls the FS5000 via the PC printer port
Adapter card or cable required
BASIC program (7 Kb)

ADAPTER CARD or CABLE
A piece of perf board with two DB25 connectors.
Some cross linked wires
Alternatively, a cable with some cross linked wires.
Circuit (184 Kb)
If using an adapter board, do not short pins 25 and 24 together or to ground,
as it will destroy part of the printed circuit board or damage the FS5000 internals.
Here is a photo of some damage and the repairs,
when an adapter was plugged vertically into the remote control connector
and it touched the black locking levers.
Damage (182k)

On-Air tests 5 April 2005
Successful copying in Sydney on 14.030MHZ at 2150 AEST
bench setup with morse key (159k)
computer arrangement (152k)
monitoring receiver RA217 (174k)

On-Air tests 13 April 2005
Successful copying in Sydney on 14.050MHz at 2130 AEST
and on 7.025MHz at 2200 AEST.
Also transmitted with an RS-1 (similar to a GRC-109) transceiver.
Similar signal strength.

FUNCTIONS

RECEIVER
can be turned ON/OFF
can set the BW narrow/wide
can set the FREQUENCY (set 7 digits)

TRANSMITTER
can be turned ON/OFF
can set the FREQUENCY (set 7 digits)
transmitter emits RF at 200KHz above the set FREQUENCY
can turn the RF output ON/OFF

ATU
can be made to tune an aerial

DATA
no progress

TRANSCEIVER USE
can be used with a separate receiver and transmitter frequency
changing from RX to TX takes about 3 seconds.
changing from TX to RX takes about 1 second.

PROTOTYPE 2
January 2007
I constructed a breadboard control unit using a PICAXE 40X.
Programming the PCAXE. Wrote the program in PICAXE BASIC and uploaded it through the serial port.
It uses an LCD display and a HEX keypad.
Works well. Several bugs were found and fixed.
LCD initialisation bug fixed.
Keyboard scanning bug fixed.
Still crashes occasionally.
Rats Nest breadboard setup

PROTOTYPE 3
January 2008
Received a metal box from Jim (thanks very much).
Cut the box and installed the LCD display and the HEX keypad.
Began PCB design.

June 2009
Designed and tested the morse key and buzzer circuit.

November 2008
Designed and tested the software ON and OFF circuits.

February 2009
Ordered some parts, chips, sockets, buzzer.

July 2009
Finished PCB design in Protel.
Finished drawing the circuit.
Got it manufactured.
It is a 2 sided board, and using snap pins for the plate through holes.
No solder mask or silk screen.

September 2009
Started populating PCB.
Tested morse and buzzer circuits.
Tested regulator and software ON and OFF circuits.

October 2009
Soldered in resistors, capacitors, chips and sockets.
PICAXE will not program!
I damaged the old chip, so cannot use that.

November 2009
Solved the PICAXE problem!
The new PICAXE 40X-1 and 40X-2 do not need an external resonator
and do not show any waveforms on the external pins.
Also the new chips require a new editor, V5.2.7,
my older version does not recognise the new 40X-1.
Uploaded the first code.
Testing the PCB.

December 2009
Got the initialisation routines working.
Should change the interface chps to 74LS374, (then have negative going latch pulses).
Wrote LCD init routine.
The LCD init routines were difficult to get right, despite all the info on the NET.
Wrote LCD write and title routines.
Title loads OK.
LCD initilaises OK.
Rewrote keyboard scan routines for new layout.
Keyboard scans OK.
FS5000 turns ON and OFF with A key.
Bandwith changes with B key.

January 2010
Rewrote frequency input routines.
Receiver now working.
Auto ON/OFF not working, PIC is loading keyboard lines when not powered.
Transmitter working reliably, doesn't crash anymore.
Perhaps the rats-nest layout was picking up RF causing a PIC RESET.
Transmitter puts out 25 watts into dummy load.
Synth Lock status displayed on LCD.

February 2010
Tested LPF routine OK.
Redesigned the ON/OFF routine and tested it OK.
TX and RX frequency offset added OK.
Did some on air testing, had two contacts.

PROTOTYPE 3
February 2010
Finished the PCB layout.
Sent it off to be made, they were slow, boards arrived 23 February 2010.
Populated one, found some errors, hole sizes too small for diodes, fuse clips, regulator, and pins,
Hole size OK for plate throughs, and ICs, just adequate for resistors.
Buzzer did not work, the new ones I bought do not operate at 5v, like the design ones I used.
Went to the store with a 4.5v battery and slected some that did.
Works marginally, redesign this.
Operators Instructions
Software listing V2.2
Software PICAXE basic V2.2
Circuit V3.3
Unpopulated PCB
This is a downloadable PROTEL file to enable a PCB to be made.
Brookes contoller. Brookes website.
Brookes controller installed
Jims version

PROTOTYPE 4
February 2011
I redesigned the morse keyer to draw less current. It now uses 2 transistors.
I also redesigned the PCB. Originally I decided to flip it over so that chips were underneath, so that it leaves more clearance for keyboard and display. Changed my mind. I just made it smaller so that it fits in the bottom of the stepped DCU box. It now uses a ribbon cable to connect to the D25 connector.
New circuit
Unpopulated PCB
Controller completed

PROTOTYPE 5
May 2012
I purchased three Casio BOSS organiser so that I can use the QWERTY keyboard.
Determined that the keyboard matrix is 7x12 lines (5x12 needed for PCB).
Used a hot air gun to remove the SMD devices from it.
Casio BOSS organiser
Casio insides
Casio stripped of ICs
Casio keyboard
Bought some LCD displays, 2x16, 2x20, 2x40 characters.
The 2x16 display works fine.
The 2x20 display works fine, but it needs pins 1 and 2 swapped on the PCB, (GND, +5v).
The 2x40 display does not work, why?
Bought a lump of aluminium, and need to mill it to shape, to mount the LCD and keyboard.

STILL TO DO
RESET should load RX freq, it does not, why?
Only tunes in 1khz increments, yet synth requies 7 digits (10hz), why?
Add range checking on inputting frequency.
Disable morse key and audible tone, when in RX mode or synth not locked?
Add a QWERTY keyboard.
Add a 2x40 char LCD display.
Investigate what the other FS5000 control lines are for.
Investigate data modes.
Investigate an SSB generator.