diff --git a/retroload-lib/examples/formats/atari_cas/Makefile b/retroload-lib/examples/formats/atari_bin/Makefile
similarity index 75%
rename from retroload-lib/examples/formats/atari_cas/Makefile
rename to retroload-lib/examples/formats/atari_bin/Makefile
index 38a2b1c..81350bd 100644
--- a/retroload-lib/examples/formats/atari_cas/Makefile
+++ b/retroload-lib/examples/formats/atari_bin/Makefile
@@ -1,6 +1,6 @@
 include ../Makefile.inc
 
-all: rl.cas
+all: rl.bin rl.cas
 
 # https://atari800.github.io/
 run: rl.cas
@@ -10,11 +10,11 @@ run: rl.cas
 	retroload $< -o $@
 
 # https://a8cas.sourceforge.net/
-%.cas: %.img
+%.cas: %.bin
 	a8cas-convert -f c -r $< $@
 
-%.img: %.asm
+%.bin: %.asm
 	$(65XX_ASM) $< -o $@
 
 clean:
-	rm -f *.wav *.cas *.img
+	rm -f *.wav *.cas *.bin
diff --git a/retroload-lib/examples/formats/atari_cas/rl.asm b/retroload-lib/examples/formats/atari_bin/rl.asm
similarity index 100%
rename from retroload-lib/examples/formats/atari_cas/rl.asm
rename to retroload-lib/examples/formats/atari_bin/rl.asm
diff --git a/retroload-lib/examples/formats/atari_bin/rl.bin b/retroload-lib/examples/formats/atari_bin/rl.bin
new file mode 100644
index 0000000..e6bbda0
Binary files /dev/null and b/retroload-lib/examples/formats/atari_bin/rl.bin differ
diff --git a/retroload-lib/examples/formats/atari_cas/rl.cas b/retroload-lib/examples/formats/atari_bin/rl.cas
similarity index 100%
rename from retroload-lib/examples/formats/atari_cas/rl.cas
rename to retroload-lib/examples/formats/atari_bin/rl.cas
diff --git a/retroload-lib/src/Examples.ts b/retroload-lib/src/Examples.ts
index b2ee920..f11bf51 100644
--- a/retroload-lib/src/Examples.ts
+++ b/retroload-lib/src/Examples.ts
@@ -46,7 +46,7 @@ const examples: ExampleDefinition[] = [
   },
   // Atari 800 XL
   {
-    dir: 'atari_cas',
+    dir: 'atari_bin',
     file: 'rl.cas',
     options: {},
     hash: '8d36a2a696c7e27807c4d1f058fdec34',
diff --git a/retroload-lib/src/common/Utils.ts b/retroload-lib/src/common/Utils.ts
index f030534..1a7a16f 100644
--- a/retroload-lib/src/common/Utils.ts
+++ b/retroload-lib/src/common/Utils.ts
@@ -27,6 +27,19 @@ export function calculateChecksum8Xor(ba: BufferAccess, initial = 0x00) {
   return sum;
 }
 
+export function calculateChecksum8WithCarry(ba: BufferAccess) {
+  // 8 bit checksum with carry being added
+  let sum = 0;
+  for (let i = 0; i < ba.length(); i++) {
+    sum += ba.getUint8(i);
+    if (sum > 255) {
+      sum = (sum & 0xff) + 1;
+    }
+  }
+
+  return sum;
+}
+
 /**
  * https://gist.github.com/chitchcock/5112270?permalink_comment_id=3834064#gistcomment-3834064
  *
diff --git a/retroload-lib/src/conversion/ConverterManager.test.ts b/retroload-lib/src/conversion/ConverterManager.test.ts
index 292ef10..e5bd7a3 100644
--- a/retroload-lib/src/conversion/ConverterManager.test.ts
+++ b/retroload-lib/src/conversion/ConverterManager.test.ts
@@ -3,7 +3,7 @@ import {BufferAccess} from '../common/BufferAccess.js';
 import {convert} from './ConverterManager.js';
 import * as fs from 'fs';
 
-test('ConverterManager calls convert function of ConverterDefinition', () => {
+test('Format kctap is converted correctly', () => {
   const data = BufferAccess.createFromNodeBuffer(fs.readFileSync(getLocalPathByDirAndFile('kc851_tap', 'rl.com')));
 
   const result = convert(data, 'kctap', {});
@@ -11,3 +11,12 @@ test('ConverterManager calls convert function of ConverterDefinition', () => {
   const expectedData = BufferAccess.createFromNodeBuffer(fs.readFileSync(getLocalPathByDirAndFile('kc851_tap', 'rl.tap')));
   expect(result.asHexDump()).toBe(expectedData.asHexDump());
 });
+
+test('Format ataricas is converted correctly', () => {
+  const data = BufferAccess.createFromNodeBuffer(fs.readFileSync(getLocalPathByDirAndFile('atari_bin', 'rl.bin')));
+
+  const result = convert(data, 'ataricas', {});
+
+  const expectedData = BufferAccess.createFromNodeBuffer(fs.readFileSync(getLocalPathByDirAndFile('atari_bin', 'rl.cas')));
+  expect(result.asHexDump()).toBe(expectedData.asHexDump());
+});
diff --git a/retroload-lib/src/conversion/ConverterProvider.ts b/retroload-lib/src/conversion/ConverterProvider.ts
index 829f566..9aeb97c 100644
--- a/retroload-lib/src/conversion/ConverterProvider.ts
+++ b/retroload-lib/src/conversion/ConverterProvider.ts
@@ -1,6 +1,8 @@
 import {type ConverterDefinition} from './converter/ConverterDefinition.js';
+import AtariCasConverter from './converter/AtariCasConverter.js';
 import KcTapConverter from './converter/KcTapConverter.js';
 
 export const converters: ConverterDefinition[] = [
+  AtariCasConverter,
   KcTapConverter,
 ];
diff --git a/retroload-lib/src/conversion/converter/AtariCasConverter.ts b/retroload-lib/src/conversion/converter/AtariCasConverter.ts
new file mode 100644
index 0000000..9a851d2
--- /dev/null
+++ b/retroload-lib/src/conversion/converter/AtariCasConverter.ts
@@ -0,0 +1,71 @@
+import {BufferAccess} from '../../common/BufferAccess.js';
+import {calculateChecksum8WithCarry} from '../../common/Utils.js';
+import {type OptionContainer} from '../../encoding/Options.js';
+import {type ConverterDefinition} from './ConverterDefinition.js';
+
+const definition: ConverterDefinition = {
+  name: 'Atari .CAS-File',
+  identifier: 'ataricas',
+  options: [],
+  convert,
+};
+export default definition;
+
+const markerByte = 0x55;
+const blockTypeFull = 0xfc;
+const blockTypePartial = 0xfa;
+const blockTypeEndOfFile = 0xfe;
+const dataBytesPerBlock = 128;
+
+const pilotIrgLength = 20000;
+const defaultIrgLength = 250; // TODO: longer for 'ENTER'-loading
+
+function convert(data: BufferAccess, _options: OptionContainer): BufferAccess {
+  const chunks = data.chunks(dataBytesPerBlock);
+
+  // FUJI-Header, baud-block, data blocks, end of file block
+  const outBa = BufferAccess.create(8 + 8 + (chunks.length + 1) * (8 + 132));
+
+  outBa.writeAsciiString('FUJI');
+  outBa.writeUint16Le(0x0000);
+  outBa.writeUint16Le(0x0000);
+
+  outBa.writeAsciiString('baud');
+  outBa.writeUint16Le(0x0000);
+  outBa.writeUint16Le(600); // default baud rate
+
+  for (let i = 0; i < chunks.length; i++) {
+    const chunk = chunks[i];
+
+    outBa.writeAsciiString('data');
+    outBa.writeUint16Le(132);
+    outBa.writeUint16Le(i === 0 ? pilotIrgLength : defaultIrgLength);
+
+    const blockBa = BufferAccess.create(132);
+    blockBa.writeUint8(markerByte);
+    blockBa.writeUint8(markerByte);
+    const partialBlock = chunk.length() !== dataBytesPerBlock;
+    const blockType = partialBlock ? blockTypePartial : blockTypeFull;
+    blockBa.writeUint8(blockType);
+    blockBa.writeBa(partialBlock ? chunk.chunksPadded(dataBytesPerBlock, 0x00)[0] : chunk);
+    if (partialBlock) {
+      blockBa.setUint8(130, chunk.length());
+    }
+    blockBa.setUint8(131, calculateChecksum8WithCarry(blockBa));
+
+    outBa.writeBa(blockBa);
+  }
+
+  // end of file block
+  outBa.writeAsciiString('data');
+  outBa.writeUint16Le(132);
+  outBa.writeUint16Le(defaultIrgLength);
+  const endBlock = BufferAccess.create(132);
+  endBlock.writeUint8(markerByte);
+  endBlock.writeUint8(markerByte);
+  endBlock.writeUint8(blockTypeEndOfFile);
+  endBlock.setUint8(131, calculateChecksum8WithCarry(endBlock));
+  outBa.writeBa(endBlock);
+
+  return outBa;
+}
diff --git a/retroload-lib/src/encoding/adapter/atari/AtariGenericAdapter.ts b/retroload-lib/src/encoding/adapter/atari/AtariGenericAdapter.ts
index 6646861..e0f3e55 100644
--- a/retroload-lib/src/encoding/adapter/atari/AtariGenericAdapter.ts
+++ b/retroload-lib/src/encoding/adapter/atari/AtariGenericAdapter.ts
@@ -4,6 +4,7 @@ import {type OptionContainer} from '../../Options.js';
 import {type RecorderInterface} from '../../recorder/RecorderInterface.js';
 import {unidentifiable, type FormatIdentification} from '../AdapterDefinition.js';
 import {type AdapterDefinition} from '../AdapterDefinition.js';
+import {calculateChecksum8WithCarry} from '../../../common/Utils.js';
 
 const definition: AdapterDefinition = {
   name: 'Atari (Generic data)',
@@ -45,7 +46,7 @@ function encode(recorder: RecorderInterface, ba: BufferAccess, _options: OptionC
       blockBa.setUint8(130, chunkBa.length());
     }
 
-    blockBa.setUint8(131, calculateChecksum(blockBa));
+    blockBa.setUint8(131, calculateChecksum8WithCarry(blockBa));
     e.recordIrg((blockId === 0) ? pilotIrgLength : defaultIrgLength); // TODO: create option (longer values are required for "ENTER-loading")
     e.recordBytes(blockBa);
   }
@@ -55,20 +56,8 @@ function encode(recorder: RecorderInterface, ba: BufferAccess, _options: OptionC
   eofBlockBa.writeUint8(markerByte);
   eofBlockBa.writeUint8(markerByte);
   eofBlockBa.writeUint8(blockTypeEndOfFile);
-  eofBlockBa.setUint8(131, calculateChecksum(eofBlockBa));
+  eofBlockBa.setUint8(131, calculateChecksum8WithCarry(eofBlockBa));
   e.recordIrg(defaultIrgLength); // TODO: create option (longer values are required for "ENTER-loading")
   e.recordBytes(eofBlockBa);
 }
 
-function calculateChecksum(ba: BufferAccess) {
-  // 8 bit checksum with carry being added
-  let sum = 0;
-  for (let i = 0; i < ba.length(); i++) {
-    sum += ba.getUint8(i);
-    if (sum > 255) {
-      sum = (sum & 0xff) + 1;
-    }
-  }
-
-  return sum;
-}