diff --git a/shard.yml b/shard.yml
index df5c96b..2c12dda 100644
--- a/shard.yml
+++ b/shard.yml
@@ -1,5 +1,5 @@
 name: knx
-version: 1.0.2
+version: 1.0.3
 crystal: ">= 0.36.1"
 
 dependencies:
diff --git a/src/knx/address.cr b/src/knx/address.cr
index 3bd6e55..352917a 100644
--- a/src/knx/address.cr
+++ b/src/knx/address.cr
@@ -76,7 +76,8 @@ class KNX
       bits 4, :main_group
       bits 3, :middle_group
     end
-    uint8 :sub_group
+
+    field sub_group : UInt8
 
     def to_s : String
       "#{main_group}/#{middle_group}/#{sub_group}"
@@ -129,7 +130,7 @@ class KNX
       bits 4, :area_address
       bits 4, :line_address
     end
-    uint8 :device_address
+    field device_address : UInt8
 
     def to_s : String
       "#{area_address}.#{line_address}.#{device_address}"
diff --git a/src/knx/cemi.cr b/src/knx/cemi.cr
index 084b639..d5e3057 100644
--- a/src/knx/cemi.cr
+++ b/src/knx/cemi.cr
@@ -87,7 +87,7 @@ class KNX
     NumberedControl   = 0b11
   end
 
-  enum MsgCode
+  enum MsgCode : UInt8
     RawRequest              = 0x10
     DataRequest             = 0x11
     PollDataRequest         = 0x13
@@ -195,9 +195,9 @@ class KNX
   class CEMI < BinData
     endian :big
 
-    enum_field UInt8, msg_code : MsgCode = MsgCode::RawRequest
-    uint8 :info_length, value: ->{ additional_info.size }
-    bytes :additional_info, length: ->{ info_length }
+    field msg_code : MsgCode = MsgCode::RawRequest
+    field info_length : UInt8, value: ->{ additional_info.size }
+    field additional_info : Bytes, length: ->{ info_length }
 
     # ---------------------
     #    Control Fields
@@ -241,7 +241,7 @@ class KNX
       bits 1, :_reserved_ # default: 0_u8
       bool no_repeat
       bool broadcast
-      enum_bits 2, priority : Priority = Priority::LOW
+      bits 2, priority : Priority = Priority::LOW
       bool ack_requested
       bool is_error
 
@@ -262,10 +262,10 @@ class KNX
     end
 
     # When sending, setting the source address to 0 allows the router to configure
-    bytes :source_address, length: ->{ 2 }
-    bytes :destination_address, length: ->{ 2 }
+    field source_address : Bytes, length: ->{ 2 }
+    field destination_address : Bytes, length: ->{ 2 }
 
-    uint8 :data_length
+    field data_length : UInt8
 
     # In the Common EMI frame, the APDU payload is defined as follows:
 
@@ -304,7 +304,7 @@ class KNX
     # +-----------------------------------------------------------------------++-------------....
     bit_field do
       # transport protocol control information
-      enum_bits 2, tpci : TpciType = TpciType::UnnumberedData
+      bits 2, tpci : TpciType = TpciType::UnnumberedData
       bits 4, :tpci_seq_num # Sequence number when tpci is sequenced
       bits 4, :apci         # application protocol control information (What we trying to do: Read, write, respond etc)
       bits 6, :data         # Or the tail end of APCI depending on the message type
diff --git a/src/knx/connection/connect_request.cr b/src/knx/connection/connect_request.cr
index 55540d5..da26c4c 100644
--- a/src/knx/connection/connect_request.cr
+++ b/src/knx/connection/connect_request.cr
@@ -7,10 +7,10 @@ class KNX
   class ConnectRequest < BinData
     endian big
 
-    custom header : Header = Header.new
-    custom control_endpoint : HPAI = HPAI.new
-    custom data_endpoint : HPAI = HPAI.new
-    custom cri : CRI = CRI.new
+    field header : Header = Header.new
+    field control_endpoint : HPAI = HPAI.new
+    field data_endpoint : HPAI = HPAI.new
+    field cri : CRI = CRI.new
 
     def self.new(
       control : Socket::IPAddress,
@@ -36,9 +36,9 @@ class KNX
   class ConnectResponse < BinData
     endian big
 
-    custom header : Header = Header.new
-    custom error : ErrorStatus = ErrorStatus.new
-    custom control_endpoint : HPAI = HPAI.new
-    custom crd : CRD = CRD.new
+    field header : Header = Header.new
+    field error : ErrorStatus = ErrorStatus.new
+    field control_endpoint : HPAI = HPAI.new
+    field crd : CRD = CRD.new
   end
 end
diff --git a/src/knx/connection/connect_state_request.cr b/src/knx/connection/connect_state_request.cr
index 5f9cd0d..d493490 100644
--- a/src/knx/connection/connect_state_request.cr
+++ b/src/knx/connection/connect_state_request.cr
@@ -10,10 +10,10 @@ class KNX
   class ConnectStateRequest < BinData
     endian big
 
-    custom header : Header = Header.new
-    uint8 channel_id
-    enum_field UInt8, status : ConnectionError = ConnectionError::NoError
-    custom control_endpoint : HPAI = HPAI.new
+    field header : Header = Header.new
+    field channel_id : UInt8
+    field status : ConnectionError = ConnectionError::NoError
+    field control_endpoint : HPAI = HPAI.new
 
     def self.new(
       channel_id : Int,
@@ -33,8 +33,8 @@ class KNX
   class ConnectStateResponse < BinData
     endian big
 
-    custom header : Header = Header.new
-    uint8 channel_id
-    enum_field UInt8, status : ConnectionError = ConnectionError::NoError
+    field header : Header = Header.new
+    field channel_id : UInt8
+    field status : ConnectionError = ConnectionError::NoError
   end
 end
diff --git a/src/knx/connection/crd.cr b/src/knx/connection/crd.cr
index 727ac26..d887301 100644
--- a/src/knx/connection/crd.cr
+++ b/src/knx/connection/crd.cr
@@ -5,8 +5,8 @@ class KNX
 
     LENGTH = 4
 
-    uint8 length, value: ->{ 4 }
-    enum_field UInt8, connect_type : ConnectType = ConnectType::Tunnel
-    uint16 identifier
+    field length : UInt8, value: ->{ 4 }
+    field connect_type : ConnectType = ConnectType::Tunnel
+    field identifier : UInt16
   end
 end
diff --git a/src/knx/connection/cri.cr b/src/knx/connection/cri.cr
index 120c9f2..59ed63a 100644
--- a/src/knx/connection/cri.cr
+++ b/src/knx/connection/cri.cr
@@ -1,5 +1,5 @@
 class KNX
-  enum ConnectType
+  enum ConnectType : UInt8
     # Data connection used to configure a KNXnet/IP device
     DeviceManagement = 0x03
 
@@ -26,8 +26,8 @@ class KNX
 
     LENGTH = 4
 
-    uint8 length, value: ->{ 4 }
-    enum_field UInt8, connect_type : ConnectType = ConnectType::Tunnel
+    field length : UInt8, value: ->{ 4 }
+    field connect_type : ConnectType = ConnectType::Tunnel
     bit_field do
       bool bus_monitor_tunnel
       bits 4, :_reserved_
@@ -35,6 +35,6 @@ class KNX
       bool data_link_tunnel
       bits 1, :_reserved2_
     end
-    uint8 reserved
+    field reserved : UInt8
   end
 end
diff --git a/src/knx/connection/error_status.cr b/src/knx/connection/error_status.cr
index eeab677..d65553b 100644
--- a/src/knx/connection/error_status.cr
+++ b/src/knx/connection/error_status.cr
@@ -1,5 +1,5 @@
 class KNX
-  enum ConnectionError
+  enum ConnectionError : UInt8
     # The connection state is normal.
     NoError = 0
 
@@ -40,7 +40,7 @@ class KNX
   class ErrorStatus < BinData
     LENGTH = 2
 
-    uint8 length, value: ->{ 1 }
-    enum_field UInt8, status : ConnectionError = ConnectionError::NoError
+    field length : UInt8, value: ->{ 1 }
+    field status : ConnectionError = ConnectionError::NoError
   end
 end
diff --git a/src/knx/connection/tunnel_request.cr b/src/knx/connection/tunnel_request.cr
index 0570d20..c8f52ba 100644
--- a/src/knx/connection/tunnel_request.cr
+++ b/src/knx/connection/tunnel_request.cr
@@ -7,13 +7,13 @@ class KNX
   class TunnelRequest < BinData
     endian big
 
-    custom header : Header = Header.new
-    uint8 length, value: ->{ 4 }
-    uint8 channel_id
-    uint8 sequence
-    enum_field UInt8, status : ConnectionError = ConnectionError::NoError
+    field header : Header = Header.new
+    field length : UInt8, value: ->{ 4 }
+    field channel_id : UInt8
+    field sequence : UInt8
+    field status : ConnectionError = ConnectionError::NoError
 
-    custom cemi : CEMI = CEMI.new
+    field cemi : CEMI = CEMI.new
 
     def self.new(
       channel_id : Int,
@@ -44,10 +44,10 @@ class KNX
   class TunnelResponse < BinData
     endian big
 
-    custom header : Header = Header.new
-    uint8 length, value: ->{ 4 }
-    uint8 channel_id
-    uint8 sequence
-    enum_field UInt8, status : ConnectionError = ConnectionError::NoError
+    field header : Header = Header.new
+    field length : UInt8, value: ->{ 4 }
+    field channel_id : UInt8
+    field sequence : UInt8
+    field status : ConnectionError = ConnectionError::NoError
   end
 end
diff --git a/src/knx/discovery/dib.cr b/src/knx/discovery/dib.cr
index 8bdd8cc..785ab9a 100644
--- a/src/knx/discovery/dib.cr
+++ b/src/knx/discovery/dib.cr
@@ -1,5 +1,5 @@
 class KNX
-  enum DescriptionType
+  enum DescriptionType : UInt8
     DeviceInformation        = 1
     SupportedServiceFamilies
     IPConfig
@@ -8,52 +8,8 @@ class KNX
     ManufacturerData         = 0xFE
   end
 
-  # Generic block
-  class InformationBlock < BinData
-    endian :big
-
-    uint8 length
-    enum_field UInt8, description_type : DescriptionType = DescriptionType::DeviceInformation
-
-    custom device_info : DIB = DIB.new, onlyif: ->{ description_type == DescriptionType::DeviceInformation }
-    array supported_services : ServiceFamily, length: ->{ (length - 2) // 2 }, onlyif: ->{ description_type == DescriptionType::SupportedServiceFamilies }
-
-    # Ignore data for information we can't parse
-    bytes raw_data, length: ->{ length - 2 }, onlyif: ->{
-      !{
-        DescriptionType::DeviceInformation,
-        DescriptionType::SupportedServiceFamilies,
-      }.includes?(description_type)
-    }
-  end
-
-  # Specific info blocks
-  class DeviceInfo < BinData
-    endian :big
-
-    LENGTH = 54
-
-    uint8 length, value: ->{ 54 }
-    enum_field UInt8, description_type : DescriptionType = DescriptionType::DeviceInformation
-    custom info : DIB = DIB.new
-
-    {% for func in [:name, :mac_address, :multicast_address, :serial] %}
-      def {{func.id}}
-        @info.{{func.id}}
-      end
-    {% end %}
-  end
-
-  class SupportedServices < BinData
-    endian :big
-
-    uint8 length, value: ->{ families.size * 2 + 2 }
-    enum_field UInt8, description_type : DescriptionType = DescriptionType::SupportedServiceFamilies
-    array families : ServiceFamily, length: ->{ (length - 2) // 2 }
-  end
-
   @[Flags]
-  enum MediumType
+  enum MediumType : UInt8
     Reserved
     TP1
     PL110
@@ -62,19 +18,36 @@ class KNX
     IP
   end
 
+  enum FamilyType : UInt8
+    Core                = 2
+    DeviceManagement
+    Tunnelling
+    Routing
+    RemoteLogging
+    RemoteConfiguration
+    ObjectServer
+  end
+
+  class ServiceFamily < BinData
+    endian :big
+
+    field family_type : FamilyType = FamilyType::Core
+    field version : UInt8
+  end
+
   # Device Information Block
   class DIB < BinData
     endian :big
 
-    enum_field UInt8, medium : MediumType = MediumType::IP
+    field medium : MediumType = MediumType::IP
     # Device status just used to indicate if in programming mode
-    uint8 device_status
-    custom source : IndividualAddress = IndividualAddress.new
-    uint16 project_installation_id
-    bytes device_serial, length: ->{ 6 }
-    bytes device_multicast_address, length: ->{ 4 }
-    bytes device_mac_address, length: ->{ 6 }
-    string friendly_name, length: ->{ 30 }
+    field device_status : UInt8
+    field source : IndividualAddress = IndividualAddress.new
+    field project_installation_id : UInt16
+    field device_serial : Bytes, length: ->{ 6 }
+    field device_multicast_address : Bytes, length: ->{ 4 }
+    field device_mac_address : Bytes, length: ->{ 6 }
+    field friendly_name : String, length: ->{ 30 }
 
     def programming_mode?
       @device_status > 0
@@ -97,20 +70,47 @@ class KNX
     end
   end
 
-  enum FamilyType
-    Core                = 2
-    DeviceManagement
-    Tunnelling
-    Routing
-    RemoteLogging
-    RemoteConfiguration
-    ObjectServer
+  # Generic block
+  class InformationBlock < BinData
+    endian :big
+
+    field length : UInt8
+    field description_type : DescriptionType = DescriptionType::DeviceInformation
+
+    field device_info : DIB = DIB.new, onlyif: ->{ description_type == DescriptionType::DeviceInformation }
+    field supported_services : Array(ServiceFamily), length: ->{ (length - 2) // 2 }, onlyif: ->{ description_type == DescriptionType::SupportedServiceFamilies }
+
+    # Ignore data for information we can't parse
+    field raw_data : Bytes, length: ->{ length - 2 }, onlyif: ->{
+      !{
+        DescriptionType::DeviceInformation,
+        DescriptionType::SupportedServiceFamilies,
+      }.includes?(description_type)
+    }
   end
 
-  class ServiceFamily < BinData
+  # Specific info blocks
+  class DeviceInfo < BinData
+    endian :big
+
+    LENGTH = 54
+
+    field length : UInt8, value: ->{ 54 }
+    field description_type : DescriptionType = DescriptionType::DeviceInformation
+    field info : DIB = DIB.new
+
+    {% for func in [:name, :mac_address, :multicast_address, :serial] %}
+      def {{func.id}}
+        @info.{{func.id}}
+      end
+    {% end %}
+  end
+
+  class SupportedServices < BinData
     endian :big
 
-    enum_field UInt8, family_type : FamilyType = FamilyType::Core
-    uint8 version
+    field length : UInt8, value: ->{ families.size * 2 + 2 }
+    field description_type : DescriptionType = DescriptionType::SupportedServiceFamilies
+    field families : Array(ServiceFamily), length: ->{ (length - 2) // 2 }
   end
 end
diff --git a/src/knx/discovery/hpai.cr b/src/knx/discovery/hpai.cr
index c8ddc99..6f8787c 100644
--- a/src/knx/discovery/hpai.cr
+++ b/src/knx/discovery/hpai.cr
@@ -1,5 +1,5 @@
 class KNX
-  enum ProtocolType
+  enum ProtocolType : UInt8
     IPv4UDP = 1
     IPv4TCP = 2
   end
@@ -10,10 +10,10 @@ class KNX
 
     LENGTH = 8
 
-    uint8 length, default: 8_u8
-    enum_field UInt8, protocol : ProtocolType = ProtocolType::IPv4UDP
-    bytes ip_addr, length: ->{ 4 }
-    uint16 port
+    field length : UInt8 = 8_u8
+    field protocol : ProtocolType = ProtocolType::IPv4UDP
+    field ip_addr : Bytes, length: ->{ 4 }
+    field port : UInt16
 
     def self.new(ip : Socket::IPAddress)
       hpai = HPAI.new
diff --git a/src/knx/discovery/search_request.cr b/src/knx/discovery/search_request.cr
index b51b464..3a5a502 100644
--- a/src/knx/discovery/search_request.cr
+++ b/src/knx/discovery/search_request.cr
@@ -8,8 +8,8 @@ class KNX
   class SearchRequest < BinData
     endian big
 
-    custom header : Header = Header.new
-    custom address : HPAI = HPAI.new
+    field header : Header = Header.new
+    field address : HPAI = HPAI.new
 
     def self.new(ip : Socket::IPAddress, protocol : ProtocolType = ProtocolType::IPv4UDP)
       request = SearchRequest.new
@@ -41,9 +41,9 @@ class KNX
   class SearchResponse < BinData
     endian big
 
-    custom header : Header = Header.new
-    custom address : HPAI = HPAI.new
-    custom device : DeviceInfo = DeviceInfo.new
-    custom services : SupportedServices = SupportedServices.new
+    field header : Header = Header.new
+    field address : HPAI = HPAI.new
+    field device : DeviceInfo = DeviceInfo.new
+    field services : SupportedServices = SupportedServices.new
   end
 end
diff --git a/src/knx/header.cr b/src/knx/header.cr
index 2ea34cc..b3b2537 100644
--- a/src/knx/header.cr
+++ b/src/knx/header.cr
@@ -1,7 +1,7 @@
 # frozen_string_literal: true, encoding: ASCII-8BIT
 
 class KNX
-  enum RequestTypes
+  enum RequestTypes : UInt16
     SearchRequest              = 0x0201
     SearchResponse             = 0x0202
     DescriptionRequest         = 0x0203
@@ -43,31 +43,33 @@ class KNX
   class Header < BinData
     endian big
 
-    uint8 :header_length, default: 0x06 # Length 6 (always for version 1)
-    uint8 :version, default: 0x10_u8    # version 1
-    enum_field UInt16, request_type : RequestTypes = RequestTypes::RoutingIndication
-    uint16 :request_length
+    field header_length : UInt8 = 0x06 # Length 6 (always for version 1)
+    field version : UInt8 = 0x10_u8    # version 1
+    field request_type : RequestTypes = RequestTypes::RoutingIndication
+    field request_length : UInt16
 
     # See: https://youtu.be/UjOBudAG654?t=42m20s
     group :wrapper, onlyif: ->{ request_type == RequestTypes::SecureWrapper } do
-      uint16 :session_id # Not sure what this should be
+      field session_id : UInt16 # Not sure what this should be
 
       bit_field do
         bits 48, :timestamp         # Timestamp for multicast messages, sequence number for tunneling
         bits 48, :knx_serial_number # Serial of the device - random constant
       end
-      uint16 :message_tag # Random number
+
+      # Random number
+      field message_tag : UInt16
 
       # header + security info + cbc_mac == 38
       #   6          16            16    == 38
-      string :encrypted_frame, length: ->{ parent.request_length - 38 }
+      field encrypted_frame : String, length: ->{ parent.request_length - 38 }
       # Encryption: Timestamp + Serial Number + Tag + 0x01 + counter (1 byte), starting at 0
       # Single key for each multicast group: PID_BACKBONE_KEY
       # https://en.wikipedia.org/wiki/CCM_mode
 
       # https://en.wikipedia.org/wiki/CBC-MAC (always 128bit (16bytes) in KNX)
       # Timestamp + Serial Number + Tag + frame length (2 bytes)
-      string :cmac, length: ->{ 16 }
+      field cmac : String, length: ->{ 16 }
     end
 
     group :timer, onlyif: ->{ request_type == RequestTypes::SecureTimerNotify } do
@@ -75,10 +77,10 @@ class KNX
         bits 48, :timestamp         # Current time as understood by the device
         bits 48, :knx_serial_number # Serial of the device
       end
-      uint16 :message_tag # Random number
+      field message_tag : UInt16 # Random number
 
       # Timestamp + Serial Number + Tag + frame length (2 bytes) == 0x0000
-      string :cmac, length: ->{ 16 }
+      field cmac : String, length: ->{ 16 }
     end
   end
 end
diff --git a/src/knx/object_server/datagram.cr b/src/knx/object_server/datagram.cr
index c9afbd6..c1fca16 100644
--- a/src/knx/object_server/datagram.cr
+++ b/src/knx/object_server/datagram.cr
@@ -1,9 +1,9 @@
 class KNX
   class ObjectServer
     class Datagram < BinData
-      custom knx_header : KNX::Header = KNX::Header.new
-      custom connection : ConnectionHeader = ConnectionHeader.new
-      custom header : ObjectHeader = ObjectHeader.new
+      field knx_header : KNX::Header = KNX::Header.new
+      field connection : ConnectionHeader = ConnectionHeader.new
+      field header : ObjectHeader = ObjectHeader.new
 
       def error
         @header.error
diff --git a/src/knx/object_server/item.cr b/src/knx/object_server/item.cr
index ab460b7..639725d 100644
--- a/src/knx/object_server/item.cr
+++ b/src/knx/object_server/item.cr
@@ -20,8 +20,8 @@ class KNX
     class Item < BinData
       endian :big
 
-      uint16 :id
-      uint8 :request_flags
+      field id : UInt16
+      field request_flags : UInt8
 
       # Request layout
       # bit_field do
@@ -98,8 +98,8 @@ class KNX
         value
       end
 
-      uint8 :value_length, value: ->{ value.size.to_u8 }
-      bytes :value, length: ->{ value_length }
+      field value_length : UInt8, value: ->{ value.size.to_u8 }
+      field value : Bytes, length: ->{ value_length }
     end
   end
 end
diff --git a/src/knx/object_server/object_header.cr b/src/knx/object_server/object_header.cr
index 546cb5a..e1425c4 100644
--- a/src/knx/object_server/object_header.cr
+++ b/src/knx/object_server/object_header.cr
@@ -1,21 +1,23 @@
+require "./item"
+
 class KNX
   class ObjectServer
     class ConnectionHeader < BinData
       endian :big
 
-      uint8 :header_length, default: 0x04
-      uint8 :reserved1, default: 0x00
-      uint8 :reserved2, default: 0x00
-      uint8 :reserved3, default: 0x00
+      field header_length : UInt8 = 0x04
+      field reserved1 : UInt8 = 0x00
+      field reserved2 : UInt8 = 0x00
+      field reserved3 : UInt8 = 0x00
     end
 
-    enum Filter
+    enum Filter : UInt8
       AllValues     = 0
       ValidValues
       UpdatedValues
     end
 
-    enum Error
+    enum Error : UInt8
       NoError             = 0
       DeviceInternalError
       NoItemFound
@@ -33,18 +35,18 @@ class KNX
     class ObjectHeader < BinData
       endian :big
 
-      uint8 :main_service, default: 0xF0
-      uint8 :sub_service
-      uint16 :start_item
-      uint16 :item_count
+      field main_service : UInt8 = 0xF0
+      field sub_service : UInt8
+      field start_item : UInt16
+      field item_count : UInt16
 
       property filter : Filter?
 
-      enum_field UInt8, _filter : Filter = Filter::ValidValues, value: ->{ filter ? filter : _filter }, onlyif: ->{ filter }
-      enum_field UInt8, error : Error = Error::NoError, onlyif: ->{ item_count == 0 }
+      field _filter : Filter = Filter::ValidValues, value: ->{ filter ? filter : _filter }, onlyif: ->{ filter }
+      field error : Error = Error::NoError, onlyif: ->{ item_count == 0 }
 
       # Requests or Statuses
-      array items : Item, length: ->{ item_count }
+      field items : Array(Item), length: ->{ item_count }
     end
   end
 end
diff --git a/src/knx/routing/indication_request.cr b/src/knx/routing/indication_request.cr
index b415390..bf44083 100644
--- a/src/knx/routing/indication_request.cr
+++ b/src/knx/routing/indication_request.cr
@@ -2,9 +2,9 @@ class KNX
   class IndicationRequest < BinData
     endian big
 
-    custom header : Header = Header.new
-    custom cemi : CEMI = CEMI.new
-    bytes extended_bytes, length: ->{ header.request_length - 17 - cemi.info_length }
+    field header : Header = Header.new
+    field cemi : CEMI = CEMI.new
+    field extended_bytes : Bytes, length: ->{ header.request_length - 17 - cemi.info_length }
 
     def payload : Bytes
       data_length = @header.request_length - 17 - @cemi.info_length