diff --git a/src/sccp_codec.erl b/src/sccp_codec.erl
new file mode 100644
index 0000000..4b7be6a
--- /dev/null
+++ b/src/sccp_codec.erl
@@ -0,0 +1,183 @@
+% ITU-T Q.71x SCCP Message coding / decoding
+
+% (C) 2010 by Harald Welte <laforge@gnumonks.org>
+%
+% All Rights Reserved
+%
+% This program is free software; you can redistribute it and/or modify
+% it under the terms of the GNU Affero General Public License as
+% published by the Free Software Foundation; either version 3 of the
+% License, or (at your option) any later version.
+%
+% This program is distributed in the hope that it will be useful,
+% but WITHOUT ANY WARRANTY; without even the implied warranty of
+% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+% GNU General Public License for more details.
+%
+% You should have received a copy of the GNU Affero General Public License
+% along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+-module(sccp_codec).
+-author('Harald Welte <laforge@gnumonks.org>').
+-include("sccp.hrl").
+
+-export([parse_sccp_msg/1, encode_sccp_msg/1, encode_sccp_msgt/2]).
+
+-compile(export_all).
+
+
+% parse SCCP Optional Part
+parse_sccp_opt(OptType, OptLen, Content) ->
+	{OptType, {OptLen, Content}}.
+
+parse_sccp_opts(<<>>, OptList) ->
+	% empty list
+	OptList;
+parse_sccp_opts(<<0>>, OptList) ->
+	% end of options
+	OptList;
+parse_sccp_opts(OptBin, OptList) ->
+	<<OptType, OptLen, Content:OptLen/binary, Remain/binary>> = OptBin,
+	NewOpt = parse_sccp_opt(OptType, OptLen, Content),
+	parse_sccp_opts(Remain, [NewOpt|OptList]).
+
+% Parse incoming SCCP message, one function for every message type
+parse_sccp_msgt(?SCCP_MSGT_CR, DataBin) ->
+	% first get the fixed part
+	<<_:8, SrcLocalRef:24, ProtoClass:8, RemainVar/binary >> = DataBin,
+	% variable length fixed part
+	<<PtrVar:8, PtrOpt:8, _/binary>> = RemainVar,
+	CalledPartyLen = binary:at(RemainVar, PtrVar),
+	CalledParty = binary:part(RemainVar, PtrVar+1, CalledPartyLen),
+	% optional part
+	OptBin = binary:part(RemainVar, 1 + PtrOpt, byte_size(RemainVar)-(1+PtrOpt)),
+	OptList = parse_sccp_opts(OptBin, []),
+	%OptList = [],
+	% build parsed list of message
+	[{src_local_ref, SrcLocalRef},{protocol_class, ProtoClass},{called_party_addr, CalledParty}|OptList];
+parse_sccp_msgt(?SCCP_MSGT_CC, DataBin) ->
+	% first get the fixed part
+	<<_:8, DstLocalRef:24, SrcLocalRef:24, ProtoClass:8, Remain/binary >> = DataBin,
+	% optional part
+	OptList = parse_sccp_opts(Remain, []),
+	% build parsed list of message
+	[{dst_local_ref, DstLocalRef},{src_local_ref, SrcLocalRef},{protocol_class, ProtoClass}|OptList];
+parse_sccp_msgt(?SCCP_MSGT_CREF, DataBin) ->
+	% first get the fixed part
+	<<_:8, DstLocalRef:24, RefusalCause:8, Remain/binary >> = DataBin,
+	% optional part
+	OptList = parse_sccp_opts(Remain, []),
+	% build parsed list of message
+	[{dst_local_ref, DstLocalRef},{refusal_cause, RefusalCause}|OptList];
+parse_sccp_msgt(?SCCP_MSGT_RLSD, DataBin) ->
+	<<_:8, DstLocalRef:24, SrcLocalRef:24, ReleaseCause:8, Remain/binary >> = DataBin,
+	% optional part
+	OptList = parse_sccp_opts(Remain, []),
+	% build parsed list of message
+	[{dst_local_ref, DstLocalRef},{src_local_ref, SrcLocalRef},{release_cause, ReleaseCause}|OptList];
+parse_sccp_msgt(?SCCP_MSGT_RLC, DataBin) ->
+	<<_:8, DstLocalRef:24, SrcLocalRef:24>> = DataBin,
+	% build parsed list of message
+	[{dst_local_ref, DstLocalRef},{src_local_ref, SrcLocalRef}];
+parse_sccp_msgt(?SCCP_MSGT_DT1, DataBin) ->
+	<<_:8, DstLocalRef:24, SegmReass:8, DataPtr:8, Remain/binary >> = DataBin,
+	DataLen = binary:at(Remain, DataPtr-1),
+	UserData = binary:part(Remain, DataPtr-1+1, DataLen),
+	% build parsed list of message
+	[{dst_local_ref, DstLocalRef},{segm_reass, SegmReass},{user_data, UserData}];
+parse_sccp_msgt(?SCCP_MSGT_DT2, DataBin) ->
+	<<_:8, DstLocalRef:24, SeqSegm:16, DataPtr:8, Remain/binary >> = DataBin,
+	DataLen = binary:at(Remain, DataPtr-1),
+	UserData = binary:part(Remain, DataPtr-1+1, DataLen),
+	% build parsed list of message
+	[{dst_local_ref, DstLocalRef},{seq_segm, SeqSegm},{user_data, UserData}];
+parse_sccp_msgt(?SCCP_MSGT_AK, DataBin) ->
+	<<_:8, DstLocalRef:24, RxSeqnr:8, Credit:8>> = DataBin,
+	[{dst_local_ref, DstLocalRef},{rx_seq_nr, RxSeqnr},{credit, Credit}];
+parse_sccp_msgt(?SCCP_MSGT_UDT, DataBin) ->
+	<<_:8, ProtoClass:8, CalledPartyPtr:8, CallingPartyPtr:8, DataPtr:8, Remain/binary >> = DataBin,
+	% variable part
+	CalledPartyLen = binary:at(Remain, CalledPartyPtr-3),
+	CalledParty = binary:part(Remain, CalledPartyPtr-3+1, CalledPartyLen),
+	CallingPartyLen = binary:at(Remain, CallingPartyPtr-2),
+	CallingParty = binary:part(Remain, CallingPartyPtr-2+1, CallingPartyLen),
+	DataLen = binary:at(Remain, DataPtr-1),
+	UserData = binary:part(Remain, DataPtr-1+1, DataLen),
+	[{protocol_class, ProtoClass},{called_party_addr, CalledParty},
+	 {calling_party_addr, CallingParty},{user_data, UserData}];
+parse_sccp_msgt(?SCCP_MSGT_UDTS, DataBin) ->
+	parse_sccp_msgt(?SCCP_MSGT_UDT, DataBin);
+parse_sccp_msgt(?SCCP_MSGT_ED, DataBin) ->
+	<<_:8, DstLocalRef:24, DataPtr:8, Remain/binary>> = DataBin,
+	DataLen = binary:at(Remain, DataPtr-1),
+	UserData = binary:part(Remain, DataPtr-1+1, DataLen),
+	[{dst_local_ref, DstLocalRef}, {user_data, UserData}];
+parse_sccp_msgt(?SCCP_MSGT_EA, DataBin) ->
+	<<_:8, DstLocalRef:24>> = DataBin,
+	[{dst_local_ref, DstLocalRef}];
+parse_sccp_msgt(?SCCP_MSGT_RSR, DataBin) ->
+	<<_:8, DstLocalRef:24, SrcLocalRef:24, ResetCause:8>> = DataBin,
+	[{dst_local_ref, DstLocalRef},{src_local_ref, SrcLocalRef},{reset_cause, ResetCause}];
+parse_sccp_msgt(?SCCP_MSGT_RSC, DataBin) ->
+	<<_:8, DstLocalRef:24, SrcLocalRef:24>> = DataBin,
+	[{dst_local_ref, DstLocalRef},{src_local_ref, SrcLocalRef}];
+parse_sccp_msgt(?SCCP_MSGT_ERR, DataBin) ->
+	<<_:8, DstLocalRef:24, ErrCause:8>> = DataBin,
+	[{dst_local_ref, DstLocalRef},{error_cause, ErrCause}];
+parse_sccp_msgt(?SCCP_MSGT_IT, DataBin) ->
+	<<_:8, DstLocalRef:24, SrcLocalRef:24, ProtoClass:8, SegmSeq:16, Credit:8>> = DataBin,
+	[{dst_local_ref, DstLocalRef},{src_local_ref, SrcLocalRef},
+         {protocol_class, ProtoClass},{seq_segm, SegmSeq},{credit, Credit}].
+% FIXME: XUDT/XUDTS, LUDT/LUDTS
+
+% process one incoming SCCP message
+parse_sccp_msg(DataBin) ->
+	MsgType = binary:first(DataBin),
+	Parsed = parse_sccp_msgt(MsgType, DataBin),
+	{ok, #sccp_msg{msg_type = MsgType, parameters = Parsed}}.
+
+% Encoding Part
+
+encode_sccp_opt({OptNum, {DataBinLen, DataBin}}) when is_integer(OptNum) ->
+	DataBinLen8 = DataBinLen*8,
+	<<OptNum:8, DataBinLen:8, DataBin:DataBinLen8>>;
+encode_sccp_opt({OptAtom,_}) when is_atom(OptAtom) ->
+	<<>>.
+
+encode_sccp_opts([], OptEnc) ->
+	% end of options + convert to binary
+	list_to_binary([OptEnc, ?SCCP_PNC_END_OF_OPTIONAL]);
+encode_sccp_opts([CurOpt|OptPropList], OptEnc) ->
+	CurOptEnc = encode_sccp_opt(CurOpt),
+	encode_sccp_opts(OptPropList, list_to_binary([OptEnc,CurOptEnc])).
+
+	
+
+encode_sccp_msgt(?SCCP_MSGT_CR, Params) ->
+	SrcLocalRef = proplists:get_value(src_local_ref, Params),
+	ProtoClass = proplists:get_value(protocol_class, Params),
+	OptBin = encode_sccp_opts(Params, []),
+	<<?SCCP_MSGT_CR:8, SrcLocalRef:24, ProtoClass:8, OptBin/binary>>;
+encode_sccp_msgt(?SCCP_MSGT_CC, Params) ->
+	SrcLocalRef = proplists:get_value(src_local_ref, Params),
+	DstLocalRef = proplists:get_value(dst_local_ref, Params),
+	ProtoClass = proplists:get_value(protocol_class, Params),
+	OptBin = encode_sccp_opts(Params, []),
+	<<?SCCP_MSGT_CC:8, DstLocalRef:24, SrcLocalRef:24, ProtoClass:8, OptBin/binary >>;
+encode_sccp_msgt(?SCCP_MSGT_CREF, Params) ->
+	DstLocalRef = proplists:get_value(dst_local_ref, Params),
+	RefusalCause = proplists:get_value(refusal_cause, Params),
+	% FIXME
+	Remain = <<>>,
+	<<?SCCP_MSGT_CREF:8, DstLocalRef:24, RefusalCause:8, Remain/binary >>;
+encode_sccp_msgt(?SCCP_MSGT_RLSD, Params) ->
+	SrcLocalRef = proplists:get_value(src_local_ref, Params),
+	DstLocalRef = proplists:get_value(dst_local_ref, Params),
+	ReleaseCause = proplists:get_value(release_cause, Params),
+	% FIXME
+	Remain = <<>>,
+	<<?SCCP_MSGT_RLSD:8, DstLocalRef:24, SrcLocalRef:24, ReleaseCause:8, Remain/binary >>.
+
+% encode one sccp message data structure into the on-wire format
+encode_sccp_msg(#sccp_msg{msg_type = MsgType, parameters = Params}) ->
+	encode_sccp_msgt(MsgType, Params).