diff --git a/src/isup.hrl b/src/isup.hrl
new file mode 100644
index 0000000..fc6bd32
--- /dev/null
+++ b/src/isup.hrl
@@ -0,0 +1,53 @@
+% Table 1 / Q.762 - ISDN user part message acronyms
+
+-define(ISUP_MSGT_ACM).	%  Address complete
+-define(ISUP_MSGT_ANM).	%  Answer
+-define(ISUP_MSGT_APM).	%  Application transport
+-define(ISUP_MSGT_BLA).	%  Blocking acknowledgement
+-define(ISUP_MSGT_BLO).	%  Blocking
+-define(ISUP_MSGT_CCR).	%  Continuity check request
+-define(ISUP_MSGT_CFN).	%  Confusion
+-define(ISUP_MSGT_CGB).	%  Circuit group blocking
+-define(ISUP_MSGT_CGBA).%  Circuit group blocking acknowledgement
+-define(ISUP_MSGT_CGU).	%  Circuit group unblocking
+-define(ISUP_MSGT_CGUA).%  Circuit group unblocking acknowledgement
+-define(ISUP_MSGT_CON).	%  Connect
+-define(ISUP_MSGT_COT).	%  Continuity
+-define(ISUP_MSGT_CPG).	%  Call progress
+-define(ISUP_MSGT_CRG).	%  Charge information
+-define(ISUP_MSGT_CQM).	%  Circuit group query
+-define(ISUP_MSGT_CQR).	%  Circuit group query response
+-define(ISUP_MSGT_DRS).	%  Delayed release (reserved – used in 1988 version)
+-define(ISUP_MSGT_FAA).	%  Facility accepted
+-define(ISUP_MSGT_FAC).	%  Facility
+-define(ISUP_MSGT_FAR).	%  Facility request
+-define(ISUP_MSGT_FOT).	%  Forward transfer
+-define(ISUP_MSGT_FRJ).	%  Facility reject
+-define(ISUP_MSGT_GRA).	%  Circuit group reset acknowledgement
+-define(ISUP_MSGT_GRS).	%  Circuit group reset
+-define(ISUP_MSGT_IAM).	%  Initial address
+-define(ISUP_MSGT_IDR).	%  Identification request
+-define(ISUP_MSGT_IRS).	%  Identification response
+-define(ISUP_MSGT_INF).	%  Information
+-define(ISUP_MSGT_INR).	%  Information request
+-define(ISUP_MSGT_LPA).	%  Loop back acknowledgement
+-define(ISUP_MSGT_LOP).	%  Loop prevention
+-define(ISUP_MSGT_NRM).	%  Network resource management
+-define(ISUP_MSGT_OLM).	%  Overload
+-define(ISUP_MSGT_PAM).	%  Pass-along
+-define(ISUP_MSGT_PRI).	%  Pre-release information
+-define(ISUP_MSGT_REL).	%  Release
+-define(ISUP_MSGT_RES).	%  Resume
+-define(ISUP_MSGT_RLC).	%  Release complete
+-define(ISUP_MSGT_RSC).	%  Reset circuit
+-define(ISUP_MSGT_SAM).	%  Subsequent address
+-define(ISUP_MSGT_SDM).	%  Subsequent directory number
+-define(ISUP_MSGT_SGM).	%  Segmentation
+-define(ISUP_MSGT_SUS).	%  Suspend
+-define(ISUP_MSGT_UBL).	%  Unblocking
+-define(ISUP_MSGT_UBA).	%  Unblocking acknowledgement
+-define(ISUP_MSGT_UCIC).%  Unequipped circuit identification code
+-define(ISUP_MSGT_UPA).	%  User part available
+-define(ISUP_MSGT_UPT).	%  User part test
+-define(ISUP_MSGT_USR).	%  User-to-user information
+
diff --git a/src/isup_codec.erl b/src/isup_codec.erl
new file mode 100644
index 0000000..025808f
--- /dev/null
+++ b/src/isup_codec.erl
@@ -0,0 +1,118 @@
+% ITU-T Q.76x ISUPcoding / decoding
+
+% (C) 2011 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(isup_codec).
+-author('Harald Welte <laforge@gnumonks.org>').
+-include("isup.hrl").
+
+-export([parse_isup_msg/1, encode_isup_msg/1]).
+
+% References to 'Tabe C-xxx' are to Annex C of Q.767
+
+% Default case: no fixed and no variable parts, only options
+% ANM, RLC, FOT
+parse_isup_msgt(M, Bin) when
+	M == ?ISUP_MSGT_ANM;
+	M == ?ISUP_MSGT_RLC;
+	M == ?ISUP_MSGT_FOT;
+		parse_isup_opts(Bin);
+% Table C-5	Address complete
+parse_isup_msgt(?ISUP_MSGT_ACM, Bin) ->
+	<<BackCallInd:16, Remain/binary>> = Bin,
+	BciOpt = {backward_call_ind, BackCallInd},
+	Opts = parse_isup_opts(Remain)
+	[BciOpt|Opts];
+% Table C-7	Call progress
+parse_isup_msgt(?ISUP_MSGT_CPG, Bin) ->
+	<<EventInf:8, Remain/binary>> = Bin,
+	BciOpt = {event_info, EventInf},
+	Opts = parse_isup_opts(Remain)
+	[BciOpt|Opts];
+% Table C-9	Circuit group reset acknowledgement
+parse_isup_msgt(?ISUP_MSGT_GRA, Bin) ->
+	% V: Range and status
+
+% Table C-11	Connect
+parse_isup_msgt(?ISUP_MSGT_CON, Bin) ->
+	<<BackCallInd:16, Remain/binary>> = Bin,
+	BciOpt = {backward_call_ind, BackCallInd},
+	Opts = parse_isup_opts(Remain)
+	[BciOpt|Opts];
+% Table C-12	Continuity
+parse_isup_msgt(?ISUP_MSGT_COT, Bin) ->
+	<<ContInd:8>> = Bin,
+	[{continuity_ind, ContInd}];
+% Table C-16	Initial address
+parse_isup_msgt(?ISUP_MSGT_IAM, Bin) ->
+	<<CINat:8, FwCallInd:16/big, CallingCat:8, TransmReq:8, VarAndOpt/binary>> = Bin,
+	FixedOpts = [{conn_ind_nature, CINat}, {fw_call_ind, FwCallInd}, {calling_cat, CallingCat},
+		     {transm_medium_req, TransmReq}],
+	% V: Called Party Number
+	VarOpts = FIXME;
+	Opts = parse_isup_opts(Remain),
+	[FixedOpts,VarOpts,Opts];
+% Table C-17	Release
+parse_isup_msgt(?ISUP_MSGT_REL, Bin) ->
+	% V: Cause indicators
+	VarOpts = FIXME;
+	Opts = parse_isup_opts(Remain),
+	[VarOpts,Opts];
+% Table C-19	Subsequent address
+parse_isup_msgt(?ISUP_MSGT_SAM, Bin) ->
+	% V: Subsequent number
+	VarOpts = FIXME;
+	Opts = parse_isup_opts(Remain),
+	[VarOpts,Opts];
+% Table C-21	Suspend, Resume
+parse_isup_msgt(Msgt, Bin) when Msgt == ?ISUP_MSGT_RES or Msgt == ?ISUP_MSGT_SUS ->
+	<<SuspResInd:8, Remain/binary>> = Bin,
+	FixedOpts = [{susp_res_ind, SuspResInd}],
+	Opts = parse_isup_opts(Remain),
+	[FixedOpts|Opts];
+% Table C-23
+parse_isup_msgt(M, <<>>) when
+	M == ?ISUP_MSGT_BLO;
+	M == ?ISUP_MSGT_BLA;
+	M == ?ISUP_MSGT_CCR;
+	M == ?ISUP_MSGT_RSC;
+	M == ?ISUP_MSGT_UBL;
+	M == ?ISUP_MSGT_UBA ->
+		[].
+% Table C-25
+parse_isup_msgt(M, Bin) when
+	M == ?ISUP_MSGT_CGB;
+	M == ?ISUP_MSGT_CGBA;
+	M == ISUP_MSGT_CGU;
+	M == ISUP_MSGT_CGUA ->
+		<<CGMsgt:8, VarBin/binary>> = Bin,
+		FixedOpts = [{cg_supv_msgt, CGMsgt}],
+		% V: Range and status
+		VarOpts = FIXME,
+		[FixedOpts|VarOpts];
+% Table C-26	Circuit group reset
+parse_isup_msgt(?ISUP_MSGT_GRS, Bin) ->
+	% V: Range without status
+	VarOpts = FIXME,
+	VarOpts.
+
+
+parse_isup_msg(Databin) when is_binary(DataBin) ->
+	<<0:4, Cic:12/big, MsgType:8, Remain/binary>> = DataBin,
+	Opts = parse_isup_msgt(MsgType, Remain),
+	#isup_msg{cic = Cic, msg_type = MsgType, parameters = Opts}.