diff --git a/lib/biju/pdu.rb b/lib/biju/pdu.rb
index a99e3da..741b2df 100644
--- a/lib/biju/pdu.rb
+++ b/lib/biju/pdu.rb
@@ -31,17 +31,18 @@ module Biju
         user_data_length: string[52..53],
       }
       res[:sender_number] = string[22..(22 + res[:address_length])]
-      res[:user_data] = PDU.decode_user_data(
-        string[54..-1], res[:data_coding_scheme])
+      res[:user_data] = PDU.decode_user_data(string[54..-1],
+        encoding: res[:data_coding_scheme],
+        length: res[:user_data_length].hex)
 
       res
     end
 
-    def self.decode_user_data(message, encoding = '00')
+    def self.decode_user_data(message, encoding: '00', length: 0)
       encoding = data_coding_scheme(encoding) unless encoding.is_a?(Symbol)
 
       raise ArgumentError, "Unknown encoding" unless ENCODING.has_key?(:gsm7bit)
-      ENCODING[:gsm7bit].decode(message)
+      ENCODING[:gsm7bit].decode(message, length: length)
     end
 
     def self.data_coding_scheme(dcs)
diff --git a/lib/biju/pdu/gsm7bit.rb b/lib/biju/pdu/gsm7bit.rb
index b6728c6..76914a5 100644
--- a/lib/biju/pdu/gsm7bit.rb
+++ b/lib/biju/pdu/gsm7bit.rb
@@ -1,81 +1,83 @@
-module Biju::PDU
-  class GSM7Bit
-    BASIC_7BIT_CHARACTER_SET = [
-      '@', '£', '$', '¥', 'è', 'é', 'ù', 'ì', 'ò', 'Ç', "\n", 'Ø', 'ø', "\r", 'Å', 'å',
-      "\u0394", '_', "\u03a6", "\u0393", "\u039b", "\u03a9", "\u03a0","\u03a8", "\u03a3", "\u0398", "\u039e", "\e", 'Æ', 'æ', 'ß', 'É',
-      ' ', '!', '"', '#', '¤', '%', '&', '\'', '(', ')','*', '+', ',', '-', '.', '/',
-      '0', '1', '2', '3', '4', '5', '6', '7','8', '9', ':', ';', '<', '=', '>', '?',
-      '¡', 'A', 'B', 'C', 'D', 'E','F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O',
-      'P', 'Q', 'R', 'S','T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'Ä', 'Ö', 'Ñ', 'Ü', '§',
-      '¿', 'a','b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o',
-      'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 'ä', 'ö', 'ñ','ü', 'à'
-    ]
+module Biju
+  module PDU
+    class GSM7Bit
+      BASIC_7BIT_CHARACTER_SET = [
+        '@', '£', '$', '¥', 'è', 'é', 'ù', 'ì', 'ò', 'Ç', "\n", 'Ø', 'ø', "\r", 'Å', 'å',
+        "\u0394", '_', "\u03a6", "\u0393", "\u039b", "\u03a9", "\u03a0","\u03a8", "\u03a3", "\u0398", "\u039e", "\e", 'Æ', 'æ', 'ß', 'É',
+        ' ', '!', '"', '#', '¤', '%', '&', '\'', '(', ')','*', '+', ',', '-', '.', '/',
+        '0', '1', '2', '3', '4', '5', '6', '7','8', '9', ':', ';', '<', '=', '>', '?',
+        '¡', 'A', 'B', 'C', 'D', 'E','F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O',
+        'P', 'Q', 'R', 'S','T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'Ä', 'Ö', 'Ñ', 'Ü', '§',
+        '¿', 'a','b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o',
+        'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 'ä', 'ö', 'ñ','ü', 'à'
+      ]
 
-    BASIC_7BIT_CHARACTER_SET_EXTENSION = {
-      0x0A => "\n",
-      0x0D => '',
-      0x14 => '^',
-      0x1B => '',
-      0x28 => '{',
-      0x29 => '}',
-      0x2F => '\\',
-      0x3C => '[',
-      0x3D => '~',
-      0x3E => ']',
-      0x40 => '|',
-      0x65 => '€',
-    }
+      BASIC_7BIT_CHARACTER_SET_EXTENSION = {
+        0x0A => "\n",
+        0x0D => '',
+        0x14 => '^',
+        0x1B => '',
+        0x28 => '{',
+        0x29 => '}',
+        0x2F => '\\',
+        0x3C => '[',
+        0x3D => '~',
+        0x3E => ']',
+        0x40 => '|',
+        0x65 => '€',
+      }
 
-    def self.decode(string)
-      res = ''
-      next_char = 0
+      def self.decode(string, length: 0)
+        res = ''
+        next_char = 0
 
-      string.scan(/../).map(&:hex).each_with_index do |octet, i|
-        index = i % 7
-        current = ((octet & (2 ** (7 - index) - 1)) << index) | next_char
+        string.scan(/../).map(&:hex).each_with_index do |octet, i|
+          index = i % 7
+          current = ((octet & (2 ** (7 - index) - 1)) << index) | next_char
 
-        res = add_char(res, current)
+          res = add_char(res, current)
 
-        next_char = octet >> (7 - index)
-        if index == 6
-          res = add_char(res, next_char)
-          next_char = 0
+          next_char = octet >> (7 - index)
+          if index == 6
+            res = add_char(res, next_char)
+            next_char = 0
+          end
+        end
+
+        res[0..(length - 1)]
+      end
+
+      def self.encode(string)
+        res = ''
+        string.chars.each do |char|
+          if get_septet(char)
+            res << get_septet(char).reverse
+          elsif get_septet(char, escape: true)
+            res << get_septet("\e").reverse
+            res << get_septet(char, escape: true).reverse
+          end
+        end
+        res << ("0" * (8 - (res.length % 8))) unless res.length % 8 == 0
+
+        res.scan(/.{8}/).map { |octet| "%02x" % octet.reverse.to_i(2) }.join
+      end
+
+      private
+
+      def self.add_char(string, char)
+        if string[-1] == "\e"
+          string.chop << BASIC_7BIT_CHARACTER_SET_EXTENSION[char]
+        else
+          string << BASIC_7BIT_CHARACTER_SET[char]
         end
       end
 
-      res
-    end
+      def self.get_septet(char, escape: false)
+        char = (!escape ? BASIC_7BIT_CHARACTER_SET.index(char) : BASIC_7BIT_CHARACTER_SET_EXTENSION.key(char))
 
-    def self.encode(string)
-      res = ''
-      string.chars.each do |char|
-        if get_septet(char)
-          res << get_septet(char).reverse
-        elsif get_septet(char, escape: true)
-          res << get_septet("\e").reverse
-          res << get_septet(char, escape: true).reverse
-        end
+        return nil unless char
+        "%07b" % char
       end
-      res << ("0" * (8 - (res.length % 8))) unless res.length % 8 == 0
-
-      res.scan(/.{8}/).map { |octet| "%02x" % octet.reverse.to_i(2) }.join
-    end
-
-    private
-
-    def self.add_char(string, char)
-      if string[-1] == "\e"
-        string.chop << BASIC_7BIT_CHARACTER_SET_EXTENSION[char]
-      else
-        string << BASIC_7BIT_CHARACTER_SET[char]
-      end
-    end
-
-    def self.get_septet(char, escape: false)
-      char = (!escape ? BASIC_7BIT_CHARACTER_SET.index(char) : BASIC_7BIT_CHARACTER_SET_EXTENSION.key(char))
-
-      return nil unless char
-      "%07b" % char
     end
   end
 end