diff --git a/pySim/gsm_r.py b/pySim/gsm_r.py
index 3364b3d..b48469e 100644
--- a/pySim/gsm_r.py
+++ b/pySim/gsm_r.py
@@ -185,7 +185,7 @@
         super().__init__(fid='6ff4', sfid=None,
                          name='EF.Shunting', desc='Shunting', size={8, 8})
         self._construct = Struct('common_gid'/Int8ub,
-                                 'shunting_gid'/Bytes(7))
+                                 'shunting_gid'/HexAdapter(Bytes(7)))
 
 
 class EF_GsmrPLMN(LinFixedEF):
diff --git a/pySim/sysmocom_sja2.py b/pySim/sysmocom_sja2.py
index f87e45a..2edc916 100644
--- a/pySim/sysmocom_sja2.py
+++ b/pySim/sysmocom_sja2.py
@@ -142,13 +142,12 @@
                             'use_opc_instead_of_op'/Bit,
                             'algorithm'/Enum(Nibble, milenage=4, comp128v1=1, comp128v2=2, comp128v3=3))
         self._construct = Struct('cfg'/CfgByte,
-                                 'key'/Bytes(16),
-                                 'op' /
-                                 If(this.cfg.algorithm == 'milenage' and not this.cfg.use_opc_instead_of_op, Bytes(
-                                     16)),
+                                 'key'/HexAdapter(Bytes(16)),
+                                 'op'/ If(this.cfg.algorithm == 'milenage' and not this.cfg.use_opc_instead_of_op,
+                                     HexAdapter(Bytes(16))),
                                  'opc' /
-                                 If(this.cfg.algorithm == 'milenage' and this.cfg.use_opc_instead_of_op, Bytes(
-                                     16))
+                                 If(this.cfg.algorithm == 'milenage' and this.cfg.use_opc_instead_of_op,
+                                     HexAdapter(Bytes(16)))
                                  )
 
 
@@ -198,13 +197,13 @@
                             'use_opc_instead_of_op'/Bit,
                             'algorithm'/Enum(Nibble, milenage=4, sha1_aka=5, xor=15))
         self._construct = Struct('cfg'/CfgByte,
-                                 'key'/Bytes(16),
+                                 'key'/HexAdapter(Bytes(16)),
                                  'op' /
-                                 If(this.cfg.algorithm == 'milenage' and not this.cfg.use_opc_instead_of_op, Bytes(
-                                     16)),
+                                 If(this.cfg.algorithm == 'milenage' and not this.cfg.use_opc_instead_of_op,
+                                     HexAdapter(Bytes(16))),
                                  'opc' /
-                                 If(this.cfg.algorithm == 'milenage' and this.cfg.use_opc_instead_of_op, Bytes(
-                                     16))
+                                 If(this.cfg.algorithm == 'milenage' and this.cfg.use_opc_instead_of_op,
+                                     HexAdapter(Bytes(16)))
                                  )
 
 
@@ -216,13 +215,13 @@
                             'use_opc_instead_of_op'/Bit,
                             'algorithm'/Enum(Nibble, milenage=4, comp128v1=1, comp128v2=2, comp128v3=3))
         self._construct = Struct('cfg'/CfgByte,
-                                 'key'/Bytes(16),
+                                 'key'/HexAdapter(Bytes(16)),
                                  'op' /
-                                 If(this.cfg.algorithm == 'milenage' and not this.cfg.use_opc_instead_of_op, Bytes(
-                                     16)),
+                                 If(this.cfg.algorithm == 'milenage' and not this.cfg.use_opc_instead_of_op,
+                                     HexAdapter(Bytes(16))),
                                  'opc' /
-                                 If(this.cfg.algorithm == 'milenage' and this.cfg.use_opc_instead_of_op, Bytes(
-                                     16))
+                                 If(this.cfg.algorithm == 'milenage' and this.cfg.use_opc_instead_of_op,
+                                     HexAdapter(Bytes(16)))
                                  )
 
 
diff --git a/pySim/ts_31_102.py b/pySim/ts_31_102.py
index 314f3c2..066ee88 100644
--- a/pySim/ts_31_102.py
+++ b/pySim/ts_31_102.py
@@ -664,7 +664,7 @@
     def __init__(self, fid='6f80', sfid=0x14, name='EF.ICI', rec_len={28, 48},
                  desc='Incoming Call Information', **kwargs):
         super().__init__(fid=fid, sfid=sfid, name=name, desc=desc, rec_len=rec_len, **kwargs)
-        self._construct = Struct('alpha_id'/Bytes(this._.total_len-28),
+        self._construct = Struct('alpha_id'/HexAdapter(Bytes(this._.total_len-28)),
                                  'len_of_bcd_contents'/Int8ub,
                                  'ton_npi'/Int8ub,
                                  'call_number'/BcdAdapter(Bytes(10)),
@@ -673,14 +673,14 @@
                                  'date_and_time'/BcdAdapter(Bytes(7)),
                                  'duration'/Int24ub,
                                  'status'/Byte,
-                                 'link_to_phonebook'/Bytes(3))
+                                 'link_to_phonebook'/HexAdapter(Bytes(3)))
 
 # TS 31.102 Section 4.2.34
 class EF_OCI(CyclicEF):
     def __init__(self, fid='6f81', sfid=0x15, name='EF.OCI', rec_len={27, 47},
                  desc='Outgoing Call Information', **kwargs):
         super().__init__(fid=fid, sfid=sfid, name=name, desc=desc, rec_len=rec_len, **kwargs)
-        self._construct = Struct('alpha_id'/Bytes(this._.total_len-27),
+        self._construct = Struct('alpha_id'/HexAdapter(Bytes(this._.total_len-27)),
                                  'len_of_bcd_contents'/Int8ub,
                                  'ton_npi'/Int8ub,
                                  'call_number'/BcdAdapter(Bytes(10)),
@@ -688,7 +688,7 @@
                                  'ext5_record_id'/Int8ub,
                                  'date_and_time'/BcdAdapter(Bytes(7)),
                                  'duration'/Int24ub,
-                                 'link_to_phonebook'/Bytes(3))
+                                 'link_to_phonebook'/HexAdapter(Bytes(3)))
 
 # TS 31.102 Section 4.2.35
 class EF_ICT(CyclicEF):
@@ -727,7 +727,7 @@
     def __init__(self, fid='6f57', sfid=None, name='EF.ACL', size={32, None},
                  desc='Access Point Name Control List', **kwargs):
         super().__init__(fid, sfid=sfid, name=name, desc=desc, size=size, **kwargs)
-        self._construct = Struct('num_of_apns'/Int8ub, 'tlvs'/GreedyBytes)
+        self._construct = Struct('num_of_apns'/Int8ub, 'tlvs'/HexAdapter(GreedyBytes))
 
 # TS 31.102 Section 4.2.51
 class EF_START_HFN(TransparentEF):
@@ -771,7 +771,7 @@
     def __init__(self, fid='6fd7', sfid=None, name='EF.MSK', desc='MBMS Service Key List', **kwargs):
         super().__init__(fid=fid, sfid=sfid, name=name, desc=desc, rec_len={20, None}, **kwargs)
         msk_ts_constr = Struct('msk_id'/Int32ub, 'timestamp_counter'/Int32ub)
-        self._construct = Struct('key_domain_id'/Bytes(3),
+        self._construct = Struct('key_domain_id'/HexAdapter(Bytes(3)),
                                  'num_msk_id'/Int8ub,
                                  'msk_ids'/msk_ts_constr[this.num_msk_id])
 # TS 31.102 Section 4.2.81
@@ -865,7 +865,8 @@
         super().__init__(fid, sfid=sfid, name=name, desc=desc, size=size, **kwargs)
         upd_status_constr = Enum(
             Byte, updated=0, not_updated=1, roaming_not_allowed=2)
-        self._construct = Struct('guti'/Bytes(12), 'last_visited_registered_tai'/Bytes(5),
+        self._construct = Struct('guti'/HexAdapter(Bytes(12)),
+                                 'last_visited_registered_tai'/HexAdapter(Bytes(5)),
                                  'eps_update_status'/upd_status_constr)
 
 # TS 31.102 Section 4.2.92
@@ -958,7 +959,8 @@
         super().__init__(fid, sfid=sfid, name=name, desc=desc, size=size, **kwargs)
         upd_status_constr = Enum(
             Byte, updated=0, not_updated=1, roaming_not_allowed=2)
-        self._construct = Struct('5g_guti'/Bytes(13), 'last_visited_registered_tai_in_5gs'/Bytes(6),
+        self._construct = Struct('5g_guti'/HexAdapter(Bytes(13)),
+                                 'last_visited_registered_tai_in_5gs'/HexAdapter(Bytes(6)),
                                  '5gs_update_status'/upd_status_constr)
 
 # TS 31.102 Section 4.4.11.7
@@ -974,7 +976,8 @@
 class EF_OPL5G(LinFixedEF):
     def __init__(self, fid='6f08', sfid=0x08, name='EF.OPL5G', desc='5GS Operator PLMN List', **kwargs):
         super().__init__(fid=fid, sfid=sfid, name=name, desc=desc, rec_len={10, None}, **kwargs)
-        Tai = Struct('mcc_mnc'/BcdAdapter(Bytes(3)), 'tac_min'/Bytes(3), 'tac_max'/Bytes(3))
+        Tai = Struct('mcc_mnc'/BcdAdapter(Bytes(3)), 'tac_min'/HexAdapter(Bytes(3)),
+                     'tac_max'/HexAdapter(Bytes(3)))
         self._construct = Struct('tai'/Tai, 'pnn_record_id'/Int8ub)
 
 # TS 31.102 Section 4.4.11.10
diff --git a/pySim/ts_51_011.py b/pySim/ts_51_011.py
index 7e7020b..c6bb194 100644
--- a/pySim/ts_51_011.py
+++ b/pySim/ts_51_011.py
@@ -667,7 +667,7 @@
 class EF_LOCI(TransparentEF):
     def __init__(self, fid='6f7e', sfid=None, name='EF.LOCI', desc='Location Information', size={11, 11}):
         super().__init__(fid, sfid=sfid, name=name, desc=desc, size=size)
-        self._construct = Struct('tmsi'/Bytes(4), 'lai'/Bytes(5), 'tmsi_time'/Int8ub,
+        self._construct = Struct('tmsi'/HexAdapter(Bytes(4)), 'lai'/HexAdapter(Bytes(5)), 'tmsi_time'/Int8ub,
                                  'lu_status'/Enum(Byte, updated=0, not_updated=1, plmn_not_allowed=2,
                                                   location_area_not_allowed=3))
 
@@ -806,7 +806,7 @@
 class EF_LOCIGPRS(TransparentEF):
     def __init__(self, fid='6f53', sfid=None, name='EF.LOCIGPRS', desc='GPRS Location Information', size={14, 14}):
         super().__init__(fid, sfid=sfid, name=name, desc=desc, size=size)
-        self._construct = Struct('ptmsi'/Bytes(4), 'ptmsi_sig'/Int8ub, 'rai'/Bytes(6),
+        self._construct = Struct('ptmsi'/HexAdapter(Bytes(4)), 'ptmsi_sig'/Int8ub, 'rai'/HexAdapter(Bytes(6)),
                                  'rau_status'/Enum(Byte, updated=0, not_updated=1, plmn_not_allowed=2,
                                                    routing_area_not_allowed=3))
 
@@ -897,7 +897,8 @@
 class EF_OPL(LinFixedEF):
     def __init__(self, fid='6fc6', sfid=None, name='EF.OPL', rec_len={8, 8}, desc='Operator PLMN List', **kwargs):
         super().__init__(fid, sfid=sfid, name=name, desc=desc, rec_len=rec_len, **kwargs)
-        self._construct = Struct('lai'/Struct('mcc_mnc'/BcdAdapter(Bytes(3)), 'lac_min'/Bytes(2), 'lac_max'/Bytes(2)), 'pnn_record_id'/Int8ub)
+        self._construct = Struct('lai'/Struct('mcc_mnc'/BcdAdapter(Bytes(3)),
+                                 'lac_min'/HexAdapter(Bytes(2)), 'lac_max'/HexAdapter(Bytes(2))), 'pnn_record_id'/Int8ub)
 
 # TS 51.011 Section 10.3.44 + TS 31.102 4.2.62
 class EF_MBI(LinFixedEF):
@@ -933,8 +934,8 @@
 class EF_MMSN(LinFixedEF):
     def __init__(self, fid='6fce', sfid=None, name='EF.MMSN', rec_len={4, 20}, desc='MMS Notification', **kwargs):
         super().__init__(fid, sfid=sfid, name=name, desc=desc, rec_len=rec_len, **kwargs)
-        self._construct = Struct('mms_status'/Bytes(2), 'mms_implementation'/Bytes(1),
-                                 'mms_notification'/Bytes(this._.total_len-4), 'ext_record_nr'/Byte)
+        self._construct = Struct('mms_status'/HexAdapter(Bytes(2)), 'mms_implementation'/HexAdapter(Bytes(1)),
+                                 'mms_notification'/HexAdapter(Bytes(this._.total_len-4)), 'ext_record_nr'/Byte)
 
 # TS 51.011 Annex K.1
 class MMS_Implementation(BER_TLV_IE, tag=0x80):