Reading and Writing tapes does not require a special utility in and of itself. Audacity, Goldwave, or any other audio recording software will work, because tapes are, in fact, just audio. There is a page devoted to how to read TRS-80 tapes into WAV format here.

What is the issue, is what to do with a WAV file once you have it. That is what this page is for. It has utilities that will convert WAVs to CAS format for use in an emulator, and back again. It has utilities that will convert high speed (1500 baud) tapes to Level II (500 baud) or even Level 1 (250 baud) and back again.

Repair WAV’s and Convert Between MANY File Formats

TRS80-Tool v2.4.0 (Win/Mac/Linux)
November 2022
Lawrence Kestleoot

TRS80-TOOL is accessible both as a web site and a stand-alone command line utility.

It’s 3 main functions are:

  1. It can try to correct a WAV file
  2. It can convert between many different formats. This includes converting from tokenized (BAS) to untokenized (ASCII), converting machine language files (CMD or SYSTEM) to disassembled listings (LST), and converting between 250 (Level 1), 500 (Level II), 1000 (LNW-80), and 1500 (Model III) baud rates. You want to take a BASIC file, a CMD file, and a SYSTEM file and put them all into a WAV file … it will do it!
  3. It can display a guessed start address for system programs with no specified start address.

TRS80-TOOL supports the following formats:

This is a BASIC program. It’s typically tokenized (token words like PRINT are stored as a single byte), but the tool supports reading Basic programs that are in text (non-tokenized) format. When writing a file with a .BAS extension, the file is always tokenized.
This is also a BASIC program, but always in text (non-tokenized) format. The extension is mostly useful when writing a BASIC file, because it tells the converter to use the non-tokenized format.
This is a cassette’s audio stream. It can be at any sampling rate, either 8 or 16 bits per sample, and either mono or stereo.
This is a cassette stored in a compact form where each bit on the cassette is stored as a bit in the file. It includes synchronization headers and bytes, as well as start bits (for high-speed cassettes). This is a decent archival format for cassettes.
This is a machine language program as stored on a floppy disk.
This is a SYSTEM file (a machine language program as stored on a cassette). The name comes from “Model 3 BiNary”. This is typically not used, and instead these files are stored within .CAS files.
This is a floppy disk format for the Model I. It’s very simple, capturing the basic sector data. It does not capture enough information for copy-protected floppies. It’s named after Jeff Vavasour.
This is a floppy disk format for the Model III. It’s very simple, capturing the basic sector data and IDAM structure. It does not capture enough information for copy-protected floppies. It’s slightly more capable than .JV1 because it can encode a mix of FM and MFM signals on the same track.
Another floppy disk format, capturing more information from the floppy, such as some bits between sectors. Named after David M. Keil.
This is an assembly language listing file, generated by disassembling a .CMD or .3BN file using the convert command.

Web Page:

This utility is in the form of an extremely powerful web page.

The web page can be found at You can drag and drop a WAV, CAS, or BAS file and from there see the individual pulses of the WAV (original and filtered). You can click on the BASIC or Machine Language output listing and see the individual clock pulses in the WAV which gave rise to whatever you are pointing to. You can run the program in a virtual emulator in the browser. And, of course, you can export the corrected WAV to WAV, BAS, Binary, or CAS.


The standalone can be found on v2.4 can be downloaded there or right here for Windows/MacOS/Linux.

Command line options are as follows:

Usage: trs80-tool COMMAND args ...


Show the tool’s version number
Show the usage message
Show the contents of WAV, CAS, JV1, JV3, DMK, and SCP files
Displays a one-line description of the contents of the file, such as its type (system program, Basic program); if known, the embedded filename; and the starting address (or its best guess for one) for SYSTEM tapes.
Displays a hex dump of the input file, with annotations. By default the command will collapse consecutive identical lines (turn off with –no-collapse. Then –color flag will force coloring on or off.
Displays a table of the sectors in a floppy disk. The columns are the sectors and the rows are the tracks. For each sector a character is displayed. The –contents flag will show the contents of each sector.
Start an interactive session for exploring the Z80. You can type an assembly language instruction (such as “ld a,5”) to assemble it, write it to memory, explain it, execute it, and show its effects on flags and registers. This virtual machine is not in a TRS-80 context (it has no ROM or peripherals).
Assembles the specified assembly language source code.
trs80-tool asm program.asm program.cmd
Assembles program.asm into program.cmd. Output can be .CMD, .3BN, .CAS, or .WAV
trs80-tool asm ‑‑baud 1500 program.asm program.cas
Assembles program.asm into a 1500 baud CAS file.
trs80-tool asm ‑‑listing program.lst program.asm program.cmd
Assembles program.asm into a program.cmd with a listing file of program.lst.
Disassembles the specified program.
trs80-tool disasm saucer.cmd
Disassembles saucer.cmd
trs80-tool disasm ‑‑org 0x8000 saucer.cmd
Disassembles saucer.cmd with an ORG of 8000H
Run a TRS-80 emulator in the shell.
trs80-tool run ‑‑model 1 ‑‑level 1
Starts a Model I Level 1 Emulator. Choices are Model I, III, and 4, Level 1 and Level II.
trs80-tool run tdos13a.dsk
Runs an emulator and boots tdos13a.dsk
Converts a list of input files to an output file or directory

The convert option is quite powerful and has three arguments of its own: –baud, –entry, and –start. Here are SOME examples that would follow trs80-tool convert on the command line, which should give you a pretty good idea of what you can accomplish:

in.cmd out.3bn
CMD file (Diskette) to SYSTEM format (Cassette)
in.bas out.asc
Detokenize file
in1.bas in2.3bn in3.cmd out.wav
3 files into a WAV file (including converting CMD to SYSTEM)
in.dmk out.wav
Diskette to WAV
in1.cas in2.cas in3.cas out.wav
3 CAS files into a single WAV file
in1.bas in2.3bn out.wav
BAS file and SYSTEM file into a single WAV file
in.cmd out.lst
Disassemble CMD file
in.3bn out.lst
Disassemble SYSTEM file
in.wav outdir
Extract the files from a WAV file to a directory
in.cas outdir
Extract the files from a CAS file to a directory
in.dmk outdir
Extract the files from a DMK file to a directory
in.wav out.wav
Clean and radically shrink the size of a WAV file

The –baud argument:

–baud 1500 in1.bas in2.3bn out.wav
BAS file and SYSTEM file into a 1,500 Baud WAV file

The –start argument:

–start 17408 in.cas out.cas
Set the start address to /17408
–start auto in.cas out.cas
Set the start address to its best guess

The –entry argument:

–entry 0x7059,0x7064,0x71B9,0x7263 lower.cas lower.lst
Disassemble the cassette file LOWER.CAS to LOWER.LST but treat locations 7059H 7064H 71B9H and 7263H as entry points. This will stop the disassembler from wrongly assuming relocated code is actually an ascii string.

Current limitations

  • Cannot write floppy disk files.
  • Can only read TRSDOS and LDOS floppy disks

Outputting CAS Files

May 2018
Knut Roll-Lund

Use your PC as a cassette player for your TRS-80 Model I/III/4 Level I and II by connecting your TRS-80 cassette input (“Ear” Output) into the PC’s headphones output.

Supports Level 1 (250 Baud), Level II (500 Baud), LNW (1kHz), and Highspeed (1500 Baud) and SYSTEM, BASIC, EDTASM, LEVEL 1 SYSTEM, and LEVEL 1 BASIC files. It does NOT support Scripsit, or ASCII files.

Convert between File Formats

TRLD v1.5.2
July 2018
George Phillips

Reads one or more TRS-80 programs in .cmd, .cas, .hex or .bas format and saves them as a single .cmd, .cas, .wav, or .hex file. As input it supports 250, 500 and 1500 baud .cas cassette image files as well as tokenized and ASCII .bas BASIC program files. Output can be in .cmd, .cas, .hex or .wav (audio file) format.

One additional feature, the “-s” option, detects relocation code and cassette loaders, runs them and puts the resuls into the output file. For example, many disk executables (.cmd) start with a short block of code that copies the entire program to a different spot in memory and jumps to it. Similarly, a few games had their own custom cassette loaders. The first program on the cassette was a short loader program that would load the rest of the tape in some custom format.

Everything below this line, while fine programs, have functionality which is included in the above programs.

Convert WAV to/from CAS

Nov 2004
Knut Roll-Lund

Convert a CAS file into a WAV for making a real TRS-80 cassette.

July 2020
Anton Argirov

Convert WAV files to CAS. It accepts WAV files with any sample rate (11025 / 22050 / 44100) and format (float / 8-bit / 16-bit / stereo / mono), uses auto-detection mechanism to get clock frequency which depends on baud rate (model I level2 500baud, level1 250baud or model III highspeed 1500 baud). Requires Ruby v2.3 to be installed.

Wav2cas is a Windows program, run in a DOS window (or you can use drag’n’drop, dropping the wav file onto the wav2cas desktop shortcut icon), which takes an uncompressed Windows wav file (made from a Model I Level II (500 Baud), Model I Level 1 (250 baud), or Model III (1500 Baud) cassette tapes) and generates a cas file for use by TRS-80 emulators. Silent bits doesn’t matter, so an entire tape can be converted (but header synchronization is only done once, so this is risky).

Convert Between CAS Speeds

Apr 2005
Knut Roll-Lund

Highlow is a small utility for converting CAS files between Highspeed (1500 Baud) and Lowspeed (500 Baud). Since 1500 Baud includes a startbit, making the file contents unreadbale, it is useful for viewing the contents of a highspeed CAS file after a wav2cas_h conversion, to do a preliminary check for success or to get the name from a system tape. It can convert both ways and does so automatically. It can’t handle multiple files in a CAS file so only single content CAS files may be used, and it must detect the header so it can’t deal with fragments.

CAS File Checker

Knut Roll-Lund

ACAS is another small utility, this time for checking the cas files. Actually it is a beta as it will be incorporated in another program but I decided that I would release this standalone version anyway. As it is now it will scan through a cas file and find out what it can about it and output what it thinks to a txt file with the same path and name.

ACAS will read model I and III type of CAS files, it will attempt to decode the first program it finds, if there are data after what it perceives as a program these will be listed as hexcodes. For highspeed it will check that the startbit is ok. It does SYSTEM tapes, reporting the blocks, does the checksum, looks for gaps. It does BASIC, listing the program detokenizing all except what is in quotes or behind a REM, checks the embedded addresses, reports any codes in quotes or behind REM.

CAS File Utility

Cass80 is a tool by J�rgen Buchm�ller to load, analyze, disassemble or list, modify, and save EACA Colour-Genie 2000 and Video-Genie 3003 (which was a TRS-80 clone) cassette images. Cass80 can be downloaded from

Mar 2005
Attila Gr�sz

Convert a /CMD file into a WAV for making a real TRS-80 cassette.