diff --git a/README.md b/README.md
index 4f8321d..436977b 100644
--- a/README.md
+++ b/README.md
@@ -147,7 +147,7 @@ Create a composer.json in your projects root-directory:
 ```json
 {
     "require": {
-        "tecnickcom/tc-lib-barcode": "^2.0"
+        "tecnickcom/tc-lib-barcode": "^2.3"
     }
 }
 ```
@@ -155,7 +155,7 @@ Create a composer.json in your projects root-directory:
 Or add to an existing project with: 
 
 ```bash
-composer require tecnickcom/tc-lib-barcode ^2.0
+composer require tecnickcom/tc-lib-barcode ^2.3
 ```
 
 ## Packaging
@@ -166,7 +166,7 @@ this library includes make targets for building these packages (`make rpm` and `
 The packages are generated under the `target` directory.
 
 When this library is installed using an RPM or DEB package, you can use it your code by including the autoloader:
-```
+```php
 require_once ('/usr/share/php/Com/Tecnick/Barcode/autoload.php');
 ```
 
diff --git a/src/Type/Square/Datamatrix.php b/src/Type/Square/Datamatrix.php
index a4c88ef..ef7bba8 100644
--- a/src/Type/Square/Datamatrix.php
+++ b/src/Type/Square/Datamatrix.php
@@ -73,32 +73,32 @@ class Datamatrix extends \Com\Tecnick\Barcode\Type\Square
     protected bool $gsonemode = false;
 
     /**
-     * Datamatrix default encoding (0=ASCII (default), 1=C40, 2=TXT, 3=X12, 4=EDF, 5=BASE256)
+     * Datamatrix default encoding.
+     * See Data::SWITCHCDW for valid values.
      */
-    protected int $encoding = Data::ENC_ASCII;
+    protected int $defenc = Data::ENC_ASCII;
 
     /**
      * Set extra (optional) parameters:
-     *     1: SHAPE - S=square (default), R=rectangular
-     *     2: MODE - N=default, GS1 = the FNC1 codeword is added in the first position of Data Matrix ECC 200 version
+     *     1: SHAPE: S=square (default), R=rectangular.
+     *     2: MODE: N=default, GS1 = the FNC1 codeword is added in the first position of Data Matrix ECC 200 version.
+     *     3: ENCODING: ASCII (default), C40, TXT, X12, EDIFACT, BASE256.
      */
     protected function setParameters(): void
     {
         parent::setParameters();
 
         // shape
-        if (isset($this->params[0]) && ($this->params[0] == 'R')) {
+        if (isset($this->params[0]) && ($this->params[0] === 'R')) {
             $this->shape = 'R';
         }
 
         // mode
-        if (isset($this->params[1]) && ($this->params[1] === 'GS1')) {
-            $this->gsonemode = true;
-        }
+        $this->gsonemode = (isset($this->params[1]) && ($this->params[1] === 'GS1'));
 
         // encoding
-        if (isset($this->params[2]) && array_key_exists(intval($this->params[2]), Data::SWITCHCDW)) {
-            $this->encoding = intval($this->params[2]);
+        if (isset($this->params[2])) {
+            $this->defenc = Data::ENCOPTS[$this->params[2]] ?? Data::ENC_ASCII;
         }
     }
 
@@ -231,7 +231,7 @@ protected function setGrid(
     protected function getHighLevelEncoding(string $data): array
     {
         // STEP A. Start in predefined encodation.
-        $enc = $this->encoding; // current encoding mode
+        $enc = $this->defenc; // current encoding mode
         $this->dmx->last_enc = $enc; // last used encoding
         $pos = 0; // current position
         $cdw = []; // array of codewords to be returned
@@ -240,8 +240,8 @@ protected function getHighLevelEncoding(string $data): array
         $field_length = 0; // number of chars in current field
 
         // Switch to predefined encoding (no action needed if ASCII because it's the default encoding)
-        if ($this->encoding !== Data::ENC_ASCII) {
-            $cdw[] = $this->dmx->getSwitchEncodingCodeword($this->encoding);
+        if ($this->defenc !== Data::ENC_ASCII) {
+            $cdw[] = $this->dmx->getSwitchEncodingCodeword($this->defenc);
             ++$cdw_num;
         }
 
diff --git a/src/Type/Square/Datamatrix/Data.php b/src/Type/Square/Datamatrix/Data.php
index f1b5004..372d3a6 100644
--- a/src/Type/Square/Datamatrix/Data.php
+++ b/src/Type/Square/Datamatrix/Data.php
@@ -89,6 +89,20 @@ class Data
      */
     public const ENC_ASCII_NUM = 7;
 
+    /**
+     * Encoding options that can be specified as input parameter.
+     *
+     * @var array<string, int>
+     */
+    public const ENCOPTS = [
+        'ASCII' => Data::ENC_ASCII,
+        'C40' => Data::ENC_C40,
+        'TXT' => Data::ENC_TXT,
+        'X12' => Data::ENC_X12,
+        'EDF' => Data::ENC_EDF,
+        'BASE256' => Data::ENC_BASE256,
+    ];
+
     /**
      * Switch codewords.
      *
diff --git a/src/Type/Square/Datamatrix/Modes.php b/src/Type/Square/Datamatrix/Modes.php
index 5ffbe6d..a659089 100644
--- a/src/Type/Square/Datamatrix/Modes.php
+++ b/src/Type/Square/Datamatrix/Modes.php
@@ -203,9 +203,10 @@ protected function getMaxDataCodewords(int $numcw): int
 
     /**
      * Get the switching codeword to a new encoding mode (latch codeword)
+     *
      * @param int $mode New encoding mode.
+     *
      * @return int Switch codeword.
-     * @protected
      */
     public function getSwitchEncodingCodeword(int $mode): int
     {
diff --git a/test/Square/DatamatrixTest.php b/test/Square/DatamatrixTest.php
index bf5d258..34777a5 100644
--- a/test/Square/DatamatrixTest.php
+++ b/test/Square/DatamatrixTest.php
@@ -393,37 +393,37 @@ public static function getGridDataProvider(): array
             ],
             // Different encoding datamatrix
             [
-                'DATAMATRIX,S,N,0', // ASCII
+                'DATAMATRIX,S,N,ASCII',
                 '01234567890',
                 'ac7dd9e1ebdb42d07fe928fb33cd307b'
             ],
             [
-                'DATAMATRIX,S,N,1', // C40
+                'DATAMATRIX,S,N,C40',
                 '01234567890',
                 '958a7a3bcd036d7135489eb703a25633'
             ],
             [
-                'DATAMATRIX,S,N,2', // TXT
+                'DATAMATRIX,S,N,TXT',
                 '01234567890',
                 '057981dfbf527b029ae59d65fb55f61d'
             ],
             [
-                'DATAMATRIX,S,N,3', // X12
+                'DATAMATRIX,S,N,X12',
                 '01234567890',
                 '8d75b0fcfb2d0977abd95004a6ba98dd'
             ],
             [
-                'DATAMATRIX,S,N,4', // EDF
+                'DATAMATRIX,S,N,EDF',
                 '01234567890',
                 '989eab3ca16c97e05dd2307bef32f64b'
             ],
             [
-                'DATAMATRIX,S,N,5', // BASE256
+                'DATAMATRIX,S,N,BASE256',
                 '01234567890',
                 '8b4f688a774130bc654e39dfcfadb482'
             ],
             [
-                'DATAMATRIX,S,GS1,1', // GS1 + C40
+                'DATAMATRIX,S,GS1,C40',
                 "\xE8" . '01095011010209171719050810ABCD1234' . "\xE8" . '2110',
                 'ba117111dfa40a40e1bb968c719d2eef'
             ]