The CasLink2 Project
Copyright (c) Alexey Podrezov, 1999-2011


The CasLink project is not dead as you might have thought. It's still alive and is being worked on. Now I am proud to present the new improved version: CasLink2. The previous CasLink version page can be found here .

You can now download the CasLink2 project files from here
Additional files required by CasLink2 project can be found here  and here .
For already encoded samples please see the Sample Files section below.

Project Overview

The main goal of CasLink and CasLink2 projects is to allow loading programs and games into MSX computers from different audio devices. All MSX computers are equipped with a cassette recorder interface that was designed to save and load software from tapes. What CasLink/CasLink2 does is basically simulating this interface. SoCasLink2 allows to transform MSX binary and ASCII files into WAV or MP3 files that can be played back to MSX using a PC sound card, a CD or MP3 player through a simple audio cable. See the cable schematics and sample files below.

CasLink/CasLink2 is created primarily for MSX users who don't have floppy disk drives in their MSX computers. It can be also a relief for those, whose disk drives are broken. Those MSX users will be able to play their favorite games on their MSX computers again with the help of CasLink2.

The next version of CasLink will also support decoding of files sent from MSX via cassette interface, so it will become a truly bi-directional application.

Main Features

CasLink2 supports encoding of the following MSX formats:

 - BAS  - tokenized or detokenized basic programs (ASCII format)
 - BIN  - binary images of ROM cartridges with startup code
 - ROM - pure images of ROM cartridges
 - SCR  - screenshots

CasLink2 supports encoding of the following BIN and ROM formats:

 - BIN  - 8/16/24/32 kb
 - ROM - 8/16/24/32 kb

CasLink2 also supports multi-file mode that allows to upload games up to 131072 bytes (1 MegaRom) long to MSX. With 3600bps speed it takes about 7 minutes. The multi-file mode supports encoding up to 15 MSX files into a single WAV or MP3 file. The CasLink2 in multi-file mode allows to upload several binary modules with or without the special basic loader before them (some games do have special basic loaders to properly setup the MSX and load binary files in a specific order). If only binary files are uploaded to MSX, each of them prepares a system for uploading the next binary, so after the first binary is uploaded, all further uploads are handled automatically.

In addition to auto-upload, CRC checking of uploaded modules was added to make sure that the modules are transferred to MSX without errors.

CasLink2 creates output files in the following formats:

 - WAV (8 bit, mono, 11 kHz)
 - WAV (16 bit, stereo, 44 kHz)
 - MP3 (uses external LAME MP3 encoder)

The following MP3 bitrates are supported:

 - 192 kbps
 - 256 kbps
 - 320 kbps

The following MSX CAS interface speeds are supported:

 - 1200 baud
 - 2400 baud
 - 3600 baud (may not work on certain MSX hardware)

The really new thing in CasLink2 project is the ability to create optimized MP3 files for different devices: PC sound card, CD player and MP3 players from 2 major manufacturers: Creative and Apple. During testing it was noticed that Creative and Apple players require different waveform to be created, so CasLink2 asks for the MP3 player type in order to create the appropriate output file.

CasLink2 was tested on the following MSX hardware:

 - Yamaha MSX1 YIS503II
 - Yamaha MSX2 YIS503III
 - Yamaha MSX2 YIS805/128

CasLink2 was tested with the following MP3 players:

 - Apple Ipod Nano (1st model)
 - Creative Muvo (64mb)
 - Creative Muvo (128mb)
 - Creative Zen (1gb)

Project Files

The CasLink2 project contains the following files:

 - caslink2.exe   (the main executable file)
 - caslink2.cpp   (source code, main C code)
 - caslink2.h      (source code, header file)
 - l32k1.bin       (compiled 32k ROM loader, part 1)
 - l32k1.mac      (32k ROM loader source, part 1)
 - l32k2.bin       (compiled 32k ROM loader, part 2)
 - l32k2.mac      (32k ROM loader source, part 2)
 - mulfload.bin   (compiled multi-file loader)
 - mulfload.mac  (multi-file loader source)
 - preload.bin     (compiled multi-file preloader)
 - preload.mac    (multi-file preloader source)
 - rloader.bin      (compiled ROM loader)
 - rloader.mac    (ROM loader source)
 - singload.bin    (compiled single file loader)
 - singload.mac   (single file loader source)
 - readme.txt      (readme file) 
 - disclaimer.txt   (disclaimer file)

The following files are required for the MP3 conversion:

 - lame.exe
 - lame_enc.dll

These files belong to the LAME MP3 encoder. It is advised to use only the codec that was tested with the CasLink2 project, namely version 3.96 MMX. You can download the LAME MP3 encoder
. After downloading, extract the 2 above mentioned encoder files into the same foder where CasLink2.exe file is located.

In order for CasLink2 main executable to work, it is required to install Microsoft Visual Studio 2005 runtime libraries that are supplied in the vcredist_x86.exe  file. This file is downloadable from Microsoft's website, as well as from here .

Command Line Options

CasLink2 is a Windows console application, so it should be started from a command interpeter (CMD.EXE ) or (much better!) from a file manager that supports console output. The best one is Far Manager, it is highly recommended:

If CasLink2 is run without command line options, it will show the command line option (key) to get help. To get help on command line options run CasLink2 executable as follows:

 caslink2 /?

The following command line options are supported:

 /e  - encode one file
 /m - encode multiple files (up to 15)
 /r  - record data from MSX into a sound file and decode it
 /d  - decode data from a WAV sound file

Please none that /r and /d options are not avilable in this version of CasLink2. They will be implemented later.

Here are some examples of command lines:

 caslink2  /e  File1.rom
 caslink2  /m  File1.rom  File2.rom
 caslink2  /m  File1.bas  File2.rom  File3.rom
 caslink2  /m  File1.bas  File2.rom  File3.bas  File4.rom  File5.rom
 caslink2  /d  File1.wav
 caslink2  /r

Please note that file names should be no longer than 12 bytes (8 bytes name, 3 bytes extension and a "."). See the Tips and Tricks section to get some tips and tricks on how to encode files of different types. The files to be encoded into a WAV or MP3 file should be in the same folder with the CasLink2.exe file.

After CasLink2 encodes the needed file into WAV or MP3 file, the only thing you need is to play this file to MSX via a simple audio cable (see instructions below). In order to MSX to start receiving the file you need to type LOAD, CLOAD or BLOAD command depending on what type of file is being uploaded. Here are some examples:

 cload"name"   - loads a tokenized Basic program named "name", the name can be up to 6 characters long
 load"cas:"      - loads a detokenized Basic program
 load"cas:",r    - loads a detokenized Basic program and runs it
 run"cas:"       - loads a detokenized Basic program and runs it
 bload"cas:"    - loads a binary program
 bload"cas:",r  - loads a binary program and runs it

For more information please see the Tips and Tricks section below. 

Caslink/Caslink2 Cable

The CasLink2 cable is a simple audio cable that is quite easy to make. Both connectors can be bought almost in every electronics shop. To make a CasLink2 cable you will need a 5 or 8 pin male connector on MSX side (to plug into MSX cassette interface) and a 3-contact stereo jack on the other side (to connect to a PC sound card, CD or MP3 player or cassette player/recorder output).

Here's a diagram of a simple CasLink cable and pictures of two connectors you need to build it:

The best way to make a universal cable (for uploading and downloading of files) is to get a 5-pin male connector, 2 female RCA type of connector of red and black color and solder them together. And then you can use a standard audio cable that has 2 male RCA type of connectors on one end and a jack, similar to the one shown above, on the other end. Here's a diagram of a proper CasLink cable and pictures of 3 parts you need to build it (the audio cable shown on the right can be purchased in any electronics store):


PLEASE NOTE that you should NOT connect red and white RCA connectors at the same time! If you want to upload games or programs to MSX, connect only white RCA connectors, if you want to download from MSX (future CasLink versions will be able to decode the downloaded files), connect only red RCA connectors. 

Tips and Tricks

The first most important tip is for setting up the sound output hardware. If you are using a PC sound card, CD or MP3 player, please make sure that the output sound is not altered in any way. You need to put Bass and Treble controls on PC to their default position, disable Bass Boost and Equilizer (or put all equilized controls to the middle - flat mode) on CD or MP3 player. If the sound is "improved" by the hardware in any way, MSX most likely will not be able to get any data from your audio source!

The second most important tip is for setting the output volume for the sound device so that MSX could "recognize" the transmission. Usually MSX is not very sensitive, so it should not take more that a few minutes to set up the volume correctly.

First, it is recommended to set the output volume to about 80%, type CLOAD, LOAD or BLOAD command (depending on what file is being played back) and start the playback of that file on your audio hardware. If MSX does not react at all, increase or decrease the volume by 10% and try again. In most of cases it does not make sense to lower the volume below 40% as MSX will not accept such a low signal.

If MSX starts to receive a file (showing FOUND or LOADING) message, upload the file fully and check that it is intact (in case of a basic program). In case of a binary file, the CasLink2 will automatically check CRC of the uploaded module and show CRC ERROR message if uploading failed. The CRC check is performed if a binary file is run.

In case you get a "Device I/O Error" message during uploading, try to increase or decrease the volume by 3-5% and re-try uploading. Once the volume is set correctly, memorize the settings - it will be easier to set it up next time.

It is recommended to choose a file encoded with 1200 baud in order to initially set up the sound volume. In case you are using MP3 file, choose the safe bitrate (256 kbps) and 1200 baud. A short basic program would be just perfect for such operation.

Here's an example of such program:

 10 cls
 20 print "Hello World!"
 30 for i = 1 to 1000
 40 next i
 50 end

Ipod Nano showed the best uploading results at all speeds and bitrates during CasLink2 project testing. But Creative players had certain problems, for example Zen player could not upload anything at 3600 baud at all. Muvo players could upload at 3600 baud, but only with 256kbps and 320kbps bitrates. The volume had to be set very precisely, otherwise upload was failing due to CRC errors.

More tips:

 - The LAME MP3 encoder files lame.exe  and lame_enc.dll  should be placed into the same folder with the CasLink2.exe   file

 - The files to be encoded into a WAV or MP3 file should be in the same folder with the CasLink2.exe   file

 - It is advised to convert all tokenized Basic programs to detokenized (ASCII) format, so they can be easily modified on a PC, the is a utility to do that conversion called LIST.EXE , it is available on some of MSX sites

 - All 8, 16, 24 and 32kb ROM and some BIN files should be uploaded without a Basic loader in front of them, here's an example of the command line:

 caslink2  /e  File1.rom
 caslink2  /m  File1.rom  File2.rom

 - When uploading several BIN files, please note that some games require a special Basic loader in order for the game to work, so you will need to modify that loader yourself, to make it work with CasLink2, here is an example:

 ----- Before -----
 30 A%=&Hc000
 40 POKE A%,0
 50 A%=A%+1
 60 POKE &Hf676,PEEK(VARPTR(A%))
 70 POKE &Hf677,PEEK(VARPTR(A%)+1)
 80 RUN"zanac-ex.GA0"

 ----- After -----
 30 A%=&Hc000
 40 POKE A%,0
 50 A%=A%+1
 60 POKE &Hf676,PEEK(VARPTR(A%))
 70 POKE &Hf677,PEEK(VARPTR(A%)+1)
 80 LOAD"cas:",R

In this case the "zanac-ex.GA0 " file is a Basic program that was run from a disk drive using the RUN command. Both files were converted to ASCII format and encoded by CasLink2 with the following command line:

  caslink2  /m  File1.bas  File2.bas  File3.bin  File4.bin

where first 2 Basic programs are loaders and the rest are game binaries. So in order for the first Basic program to load and start the second Basic program from a cassette interface, we had to change the RUN command into the LOAD"cas:",R command.

Another example:

 ----- Before -----
 1 DEFUSR=&Hd000
 4 BLOAD"WOODYPOC.GA1",-&H1000:POKE&Hd002,&H85:A=USR(0)
 5 FORT=1TO7:OUT&Hfe,T
 9 POKE&H87A4,247:POKE&H87A5,12:RETURN

 ----- After -----
 1 DEFUSR=&Hd000
 3 BLOAD"CAS:",-&H1000:A=USR(0)
 4 BLOAD"CAS:",-&H1000:POKE&Hd002,&H85:A=USR(0)
 7 BLOAD"CAS:",-&H1000
 9 POKE&H87A4,247:POKE&H87A5,12:RETURN

As you see, in this case the program loads multiple binary files in a specific order using the BLOAD"name" command. To make the program work with CasLink2, we need to change all file names to "cas:" and then encode all files in that specific order as the original Basic program loads them.

Here's the command line for this particular case (the WOODYPOC.BAS is the above shown Basic loader):


 - Sometimes a Basic loader tries to free memory and load itself again, but to a different memory address. In this case it is needed to encode such basic loader twice before the binary files. Here's an example of such loader and how it should be converted to work with CasLink2:

 ----- Before -----
 10 POKE-1,170:WIDTH80
 30 CLS:PRINT"Please wait - King Valley II is loading..."

 ----- After -----
 10 POKE-1,170:WIDTH80
 30 CLS:PRINT"Please wait - King Valley II is loading..."
 40 FORA=1TO6:BLOAD"cas:",R:NEXT

 The following command line should be used in case Basic loader may reload itself:

  caslink2  /m  File1.bas  File1.bas  File2.bin  File3.bin  File4.bin  File5.bin  File6.bin  File7.bin

 - If a game loader loads a screenshot, it is advised to remove that code and not encode the screenshot file to save loading time, however make sure that the initial screen for the game is set in the loader

 - The optimum encoding parameters are: 2400 baud for MSX cassette interface speed; 44kHz, stereo, 16 bit for a WAV file and 256kbps bitrate for an MP3 file

 - Yamaha MSX hardware was loading games at 3600 baud, which is very good because uploading a 128kb game takes 8 minutes compraing to 12 minutes with 2400 baud

It should be noted that not all multi-file megarom games can be loaded to MSX using CasLink2. In some cases it takes a lot of time to modify the game loaders so they correctly work with CasLink2. In some rare cases certain games can not be loaded at all. 

Sample Files

Below are a few sample files, both WAV and MP3, created using CasLink2. The samples allow you to test uploading of files of different types to MSX. Please note that the content may be still a copyrighted material, so I am not providing any source files that were used to create these WAVs and MP3s.

All MP3 files have 256kbps bitrate, the WAV files are in 16bit/stereo/44kHz format and are packed into ZIP archives to reduce their size. The samples were created to test only 2400 and 3600 baud speed of MSX cassette interface. Note that not all MSX hardware supports 3600 baud speed! And not all MP3 players can upload at 3600 baud!

HINT: to download a sample, rightclick on "WAV" or "MP3" and then select "Save Link As.." or "Save Target As..." option.

Sample 1 (Putup): tokenized basic program; for MSX1, 2, 2+, TurboR; load with cload"putup" command; press F5 to run.
 Creative MP3 players, 2400 baud:  WAV  MP3
 Creative MP3 players, 3600 baud:  WAV  MP3
 Apple MP3 players, CD, PC, 2400 baud:  WAV  MP3
 Apple MP3 players, CD, PC, 3600 baud:  WAV  MP3

Sample 2 (Dump): detokenized basic program; for MSX 2, 2+, TurboR; load with load"cas:",r command.
 Creative MP3 players, 2400 baud:  WAV
 Creative MP3 players, 3600 baud:  WAV  MP3
 Apple MP3 players, CD, PC, 2400 baud:  WAV  MP3
 Apple MP3 players, CD, PC, 3600 baud:  WAV  MP3

Sample 3 (King Valley): image or 16kb ROM cartridge; for MSX1, 2, 2+, TurboR; load with bload"cas:",r command.
 Creative MP3 players, 2400 baud:  WAV
 Creative MP3 players, 3600 baud:  WAV  MP3
 Apple MP3 players, CD, PC, 2400 baud:  WAV  MP3
 Apple MP3 players, CD, PC, 3600 baud:  WAV  MP3

Sample 4 (Rise Out): image of 16kb ROM cartridge with loader code; for MSX1, 2, 2+, TurboR; load with bload"cas:",r command.
 Creative MP3 players, 2400 baud:  WAV  MP3
 Creative MP3 players, 3600 baud:  WAV  MP3
 Apple MP3 players, CD, PC, 2400 baud:  WAV  MP3
 Apple MP3 players, CD, PC, 3600 baud:  WAV  MP3

Sample 5 (Hype): image or 32kb ROM cartridge; for MSX1, 2, 2+, TurboR; load with bload"cas:",r command.
 Creative MP3 players, 2400 baud:  WAV  MP3
 Creative MP3 players, 3600 baud:  WAV  MP3
 Apple MP3 players, CD, PC, 2400 baud:  WAV  MP3
 Apple MP3 players, CD, PC, 3600 baud:  WAV  MP3

Sample 6 (Polar Star): detokenized Basic loader and two BIN files; for MSX1, 2, 2+, TurboR; load with load"cas:",r command.
 Creative MP3 players, 2400 baud:  WAV  MP3
 Creative MP3 players, 3600 baud:  WAV  MP3
 Apple MP3 players, CD, PC, 2400 baud:  WAV  MP3
 Apple MP3 players, CD, PC, 3600 baud:  WAV  MP3

Sample 7 (Girly Block): eight 16kb BIN files; for MSX 2, 2+, TurboR; boot MSX with CTRL+DEL buttons pressed; load with bload"cas:",r command.
 Creative MP3 players, 2400 baud:  WAV  MP3    Warning! 24mb MP3 file!
 Creative MP3 players, 3600 baud:  WAV  MP3    Warning! 17mb MP3 file!
 Apple MP3 players, CD, PC, 2400 baud:  WAV  MP3    Warning! 24mb MP3 file!
 Apple MP3 players, CD, PC, 3600 baud:  WAV  MP3    Warning! 17mb MP3 file!

Sample 8 (Woody Poco): two basic loaders, eight 16kb BIN files; for MSX 2, 2+, TurboR; boot MSX with CTRL+DEL buttons pressed; load with load"cas:",r command.
 Creative MP3 players, 2400 baud:  WAV  MP3    Warning! 26mb MP3 file!
 Creative MP3 players, 3600 baud:  WAV  MP3    Warning! 20mb MP3 file!
 Apple MP3 players, CD, PC, 2400 baud:  WAV  MP3    Warning! 26mb MP3 file!
 Apple MP3 players, CD, PC, 3600 baud:  WAV  MP3    Warning! 20mb MP3 file!

All these samples were tested and found to be working on the hardware, available to the developer of CasLink/CasLink2 projects (see above).

Project History

Below is the history of changes made in the CasLink/CasLink2 projects by its developer:

    Name          Date            Description
 Podrezov   07/09/1999   Initial version created
 Podrezov   26/08/2005   Sources ported to Visual Studio .NET 
 Podrezov   28/08/2005   Added support for 16 bit, stereo, 44 kHz 
 Podrezov   29/08/2005   Modified ROM loaders 
 Podrezov   30/08/2005   Added sound file playback 
 Podrezov   05/09/2005   Increased parts number to 15, multifile loader modified 
 Podrezov   12/09/2005   Fixed detokenized Basic file loading bug in multifile loader routine 
 Podrezov   25/09/2005   Added preloader for BINs, ROMs 
 Podrezov   26/09/2005   Modified and recompiled ROM loaders, created BIN2INC utility 
 Podrezov   29/09/2005   Added preloader for multi-file ROMs 
 Podrezov   03/10/2005   Wrote WAV converter from CD to RD quality 
 Podrezov   14/03/2008   Sources ported to Visual Studio 2005 
 Podrezov   17/03/2008   Added MP3 conversion capability, added colors for messages 
 Podrezov   19/03/2008   Disabled signal level question (now it always is 100), fixed waveform of CD quality WAV file 
 Podrezov   21/03/2008   Added option for normal and inverted waveforms for different MP3 players 
 Podrezov   22/03/2008   Fixed a bug in WAV file length calculation when only binary files are encoded 
 Podrezov   23/03/2008   Added copyright message to WAV files, added wrong CR+LF check for input ASCII files 
 Podrezov   26/03/2008   Re-wrote all ROM loaders, created single BIN file loader, added CRC check 
 Podrezov   28/03/2008   Added 3600 baud MSX cassette I/O speed support
 Podrezov   05/08/2008   Added missing detokenized file encoding code in single file encoding routine
 Podrezov   29/10/2008   Fixed a bug in 32kb ROM loading routine, now all such ROMs should start normally


The CasLink and its successor, CasLink2 project, was developed by Alexey Podrezov. The project is distributed with the source code, so everyone can use it to develop his own MSX related tools.

The project files can be put on any public ftp and web servers, however they should be always accompanied by the readme.txt  file.

If any part of CasLink or CasLink2 code is used in any third-party utility, please mention the original author's name in the credits. You do not need to ask the author's permission to use CasLink2 code, however it would be nice to send a message to the author to let him know that his code will be used to keep MSX scene alive.

The only restriction is: CasLink and CasLink2 should not be used for commercial purposes. However if someone finds the way to make money out of it, I would be interested to hear it. Just out of curiosity... 


I would like to thank the following people who helped or inspired me to create and continue the development of CasLink/CasLink2 project:

 - Egor Voznessenskiy (R.I.P.)
 - Gennadiy Kurapov
 - Sergey Kirov
 - Ekaterina Kirova
 - Sean Young  (not the actor Sean Young)
 - Arnaud  (The File-Hunter)
 - IgorX  (whom I know only from ICQ)
 - Mihail Volkov
 - Timo Soilamaa (Nyyrikki)
 - Ahti Soilamaa
 - Saku Taipale (STT)

Contact Information

If you wish to contact the author of Caslink/CasLink2 projects - Alexey Podrezov, please feel free to send a message to the e-mail address, mentioned in the readme.txt  file. 


Alexey Podrezov
This page was created on August 5th, 2008
Last modified on August 29th, 2015