diff --git a/BSSMAP.st b/BSSMAP.st
index 865c8f9..c04ced6 100644
--- a/BSSMAP.st
+++ b/BSSMAP.st
@@ -461,25 +461,55 @@ GSM0808IE subclass: GSM0808ChosenEncrIE [
 GSM0808IE subclass: GSM0808ChannelTypeIE [
     | type preferred codecs |
 
+    <comment: 'I implement 3.2.2.11 of GSM08.08'>
+
     GSM0808ChannelTypeIE class >> speechSpeech     [ ^ 1 ]
     GSM0808ChannelTypeIE class >> speechData       [ ^ 2 ]
     GSM0808ChannelTypeIE class >> speechSignalling [ ^ 3 ]
 
     "TODO: provide defs for the 3.2.2.11 ChannelType rate"
+    GSM0808ChannelTypeIE class [
+        chanSpeechFullBm [ <category: 'ChannelType-Speech'> ^ 2r1000 ]
+        chanSpeechHalfLm [ <category: 'ChannelType-Speech'> ^ 2r1001 ]
+        chanSpeechFullPref [ <category: 'ChannelType-Speech'> ^ 2r1010 ]
+        chanSpeechHalfPref [ <category: 'ChannelType-Speech'> ^ 2r1011 ]
+        chanSpeechFullPrefNoChange [ <category: 'ChannelType-Speech'> ^ 2r11010 ]
+        chanSpeechHalfPrefNoChange [ <category: 'ChannelType-Speech'> ^ 2r11011 ]
+        chanSpeechAny [ <category: 'ChannelType-Speech'> ^ 2r1111 ]
+        chanSpeechAnyNoChange [ <category: 'ChannelType-Speec'> ^ 2r11111 ]
+
+        speechFullRateVersion1 [ <category: 'Speech-Version'> ^ 2r000001 ]
+        speechFullRateVersion2 [ <category: 'Speech-Version'> ^ 2r010001 ]
+        speechFullRateVersion3 [ <category: 'Speech-Version'> ^ 2r100001 ]
+        speechHalfRateVersion1 [ <category: 'Speech-Version'> ^ 2r000101 ]
+        speechHalfRateVersion2 [ <category: 'Speech-Version'> ^ 2r010101 ]
+        speechHalfRateVersion3 [ <category: 'Speech-Version'> ^ 2r100101 ]
+
+        buildPermittedSpeechList: aList [
+            | out |
+            out := aList asByteArray copy.
+
+            1 to: out size - 1 do: [:pos |
+                out at: pos put: ((out at: pos) bitOr: 16r80)
+            ].
+
+            ^ out
+        ]
+    ]
 
     GSM0808ChannelTypeIE class >> elementId [ ^ 11 ]
-    GSM0808ChannelTypeIE class >> initWith: aType audio: anAudioType codecs: codecs [
+    GSM0808ChannelTypeIE class >> initWith: aType audio: anAudioType [
         ^ self new
             type: aType;
             preferred: anAudioType;
-            audioCodecs: codecs;
             yourself
     ]
 
     GSM0808ChannelTypeIE class >> parseFrom: aByteArray [
-        ^ self initWith: (aByteArray at: 3)
-               audio: (aByteArray at: 4)
-               codecs: (aByteArray copyFrom: 5)
+        ^ (self initWith: (aByteArray at: 3)
+               audio: (aByteArray at: 4))
+                audioCodecs: (aByteArray copyFrom: 5);
+                yourself
     ]
 
     type [ ^ type ]
@@ -490,10 +520,15 @@ GSM0808IE subclass: GSM0808ChannelTypeIE [
     preferred [ ^ preferred ]
     preferred: aPreferred [ preferred := aPreferred ]
 
+    audioCodecs: aList [
+        <category: 'audio-codes'>
+        self audioCodecsData: (self class buildPermittedSpeechList: aList).
+    ]
+
 
     "TODO: This should decode/encode the codecs"
-    audioCodecs [ ^ codecs ]
-    audioCodecs: aCodecs [ codecs := aCodecs. ]
+    audioCodecsData [ ^ codecs ]
+    audioCodecsData: aCodecs [ codecs := aCodecs. ]
 
     writeOnDirect: aMsg [
         aMsg putByte: 2 + codecs size.
diff --git a/Tests.st b/Tests.st
index 36dfc85..87006bb 100644
--- a/Tests.st
+++ b/Tests.st
@@ -104,6 +104,22 @@ TestCase subclass: GSM0808Test [
         res := (GSM0808CICIE initWithMultiplex: 1 timeslot: 20) toMessage asByteArray.
         self assert: res = #(1 0 52) asByteArray.
     ]
+
+    testChanIE [
+        | res |
+        res := (GSM0808ChannelTypeIE buildPermittedSpeechList:
+                                {GSM0808ChannelTypeIE speechFullRateVersion3.
+                                  GSM0808ChannelTypeIE speechHalfRateVersion3}).
+        self assert: res = #(161 37) asByteArray.
+
+        res := ((GSM0808ChannelTypeIE
+                initWith: (GSM0808ChannelTypeIE speechSpeech)
+                audio: (GSM0808ChannelTypeIE chanSpeechHalfPrefNoChange))
+                    audioCodecs: {GSM0808ChannelTypeIE speechFullRateVersion3.
+                                  GSM0808ChannelTypeIE speechHalfRateVersion3};
+                    yourself).
+        self assert: res toMessage asByteArray = #(11 4 1 27 161 37) asByteArray.
+    ]
 ]
 
 TestCase subclass: BSSAPTest [