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"Casio Interface"


Casio-PC Parallel   Casio-PC Serial   Casio-Casio   Casio Links

Even if you are lucky enough to own a Casio interface for your programmable calculator, it can very frustrating trying to get it to work.  (I know from experience!) There is very little help in the User Manual, regarding PC connection.

However, it is possible to make your own PC-Casio connection cable or even transfer programs between two Calculators.

Casio-PC (Parallel Port)

Warning:  The Calculator should be switched OFF until all cable connections have been made.

Connection Cable


Four core BT telephone cable is an ideal substitute and is coloured to aid identification.

PC End

The PC Connection is made to the Parallel Printer Port (LPT1).  Using a special connector available at most good PC shops or Computer fairs, the wires may be attached to pins and located into the connector at the following locations.

PC Connector viewed from the Cable side

PC Connector


Casio End

The corresponding wires should be inserted into the following holes of the Casio Socket.  I have not come across a source for Casio connectors.  Please let me know if you know different!

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

The wires should be connected as follows...



11 22 BUSY
19 30 GROUND

Software (Spanish)

To commence communications between the PC and your Casio, it is necessary to download this Interface Program:

Casio_v14.zip (79 Kb)

The program is in Spanish, like many of the FX850P/FX880P links.  However, many of the commands are fairly straightforward.  The main ones are:

Archivo Files
Nuevo New
Abrir Open
Guardar Save
Guardar como Save as
Transmitir Transmit
Recibir Receive
Shell al DOS Shell to DOS
Salir Exit


1.    Switch on the Calculator.

2.    Select [MODE] 1.

3.    Select Program Location [ S ] 0 (to 9).

4.    Run the Casio PC Program in DOS Mode.

5a.  To Transmit (PC-Casio)

        Select "Abrir/Open".

        Select text file to be transmitted. 

        Select "Transmitir/Transmit"

        At Casio, type LOAD"CAS0:n  (n=baud ref no)  [EXE]

        Press OK at the PC to commence upload.

        Press [BRK] on the Casio at the end of the transmission.

5b.  To Receive (Casio-PC)

       Select "Recibir/Receive"

       Press OK

       At Casio, type SAVE"CAS0:n  (n=baud ref no)  [EXE]

6.    Known problems:

       Not connecting properly

            Ensure cables are fully inserted into Casio.

       Last line of uploaded file may not be transmitted

            Add a blank line or extra command eg. 200 END.

       BV (Buffer Overflow) Error

            Reduce baud rate or switch off Calculator and try again.

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Casio-PC (Serial Port)


"Dirty Fly" has written a program to transfer data between the PC and Casio via the Serial Port (Com 1 to Com 4):

FXEdit1_0  (2.3 Mb)

Connection Cable (Spanish)

A Spanish circuit diagram for a PC-Casio RS232 interface is located at the following website:

http://casiofx.metropoli2000.net/casiofx/hardware/serie.html     (Link Broken)

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Casio to Casio

To transmit programs between Casio FX850P/FX880P calculators...

Connection Cable

Two core cable is required.  Telephone cable or small speaker cable will do.

No connectors are required as the ends are simply stripped and inserted into the calculator interface sockets.

Casio Connections

Connect the wires to the calculators in the following manner:

Transmitting Calculator  Receiving Calculator  
Pin 22 Pin 5  
Pin 30 Pin 30 Ground

Casio Socket Arrangement

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30


1.    Turn on both Calculators

2.    Select [MODE] 1 on both Calculators

3.    Select Program Locations on both Calculators, [ S ] 0 (to 9)

4.    At Receiving Calculator, type,

            LOAD"COM0  [EXE]

5.    At Transmitting Calculator, type,

            SAVE"COM0  [EXE]

6.    If all is well, the Receiving Calculator will display,

            COM0      B

7.    Wait until both Calculators display,

            Ready P0 (to P9)

       before selecting next Program Locations.

8.    If an FC (Function Call) or PO (Parity) Error occurs,

       press [ BRK ] and/or switch off both Calculators and try again.

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Casio Links

I am very grateful to the following people for providing the above information, software and programs for the Casio FX850P and FX880P.



English text written by a Pole.  Source of Polish, Spanish and German programs.


http://casiofx.metropoli2000.net/  (Link Broken)

Excellent source for Spanish Programs, Hints, Utilities and the User Manual.

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