diff --git a/- b/-
deleted file mode 100644
index 80c966e..0000000
Binary files a/- and /dev/null differ
diff --git a/test_backup_restore.py b/test_backup_restore.py
index 660c11b..54812ca 100755
--- a/test_backup_restore.py
+++ b/test_backup_restore.py
@@ -8,7 +8,7 @@ import datetime
 import codecs
 from builtins import input
 
-import pickle
+import json
 
 sys.path.append("zk")
 
@@ -55,7 +55,7 @@ try:
     fp_version = conn.get_fp_version()
     print ('Serial Number    : {}'.format(serialnumber))
     print ('Finger Version   : {}'.format(fp_version))
-    filename = args.filename if args.filename else "{}.bak".format(serialnumber)
+    filename = args.filename if args.filename else "{}.json.bak".format(serialnumber)
     print ('')
     if not args.restore:
         print ('--- sizes & capacity ---')
@@ -76,29 +76,33 @@ try:
         #save to file!
         print ('')
         print ('Saving to file {} ...'.format(filename))
-        output = open(filename, 'wb')
+        output = open(filename, 'w')
         data = {
-            'version':'1.00ut',
+            'version':'1.00jut',
             'serial': serialnumber,
             'fp_version': fp_version,
-            'users': users,
-            'templates':templates
+            'users': [u.__dict__ for u in users],
+            'templates':[t.json_pack() for t in templates]
             }
-        pickle.dump(data, output, -1)
+        json.dump(data, output, indent=1)
         output.close()
     else:
         print ('Reading file {}'.format(filename))
-        infile = open(filename, 'rb')
-        data = pickle.load(infile)
+        infile = open(filename, 'r')
+        data = json.load(infile)
         infile.close()
         #compare versions...
-        if data['version'] != '1.00ut':
+        if data['version'] != '1.00jut':
             raise BasicException("file with different version... aborting!")
         if data['fp_version'] != fp_version:
             raise BasicException("fingerprint version mismmatch {} != {} ... aborting!".format(fp_version, data['fp_version']))
         #TODO: check data consistency...
-        print ("INFO: ready to write {} users".format(len(data['users'])))
-        print ("INFO: ready to write {} templates".format(len(data['templates'])))
+        users = [User.json_unpack(u) for u in data['users']]
+        #print (users)
+        print ("INFO: ready to write {} users".format(len(users)))
+        templates = [Finger.json_unpack(t) for t in data['templates']]
+        #print (templates)
+        print ("INFO: ready to write {} templates".format(len(templates)))
         #input serial number to corroborate.
         print ('WARNING! the next step will erase the current device content.')
         print ('Please input the serialnumber of this device [{}] to acknowledge the ERASING!'.format(serialnumber))
@@ -111,10 +115,12 @@ try:
         if args.clear_attendance:
             print ('Clearing attendance too!')
             conn.clear_attendance()
+        conn.read_sizes()
+        print (conn)
         print ('Restoring Data...')
-        for u in data['users']:
+        for u in users:
             #look for Templates
-            temps = list(filter(lambda f: f.uid ==u.uid, data['templates']))
+            temps = list(filter(lambda f: f.uid ==u.uid, templates))
             #print ("user {} has {} fingers".format(u.uid, len(temps)))
             conn.save_user_template(u,temps)
         conn.enable_device()
diff --git a/zk/finger.py b/zk/finger.py
index 77aab11..26de3f0 100644
--- a/zk/finger.py
+++ b/zk/finger.py
@@ -16,10 +16,26 @@ class Finger(object):
 
     def repack_only(self): #only template
         return pack("H%is" % (self.size), self.size, self.template)
-    
-    def __eq__(self, other): 
+    @staticmethod
+    def json_unpack(json):
+        return Finger(
+            uid=json['uid'],
+            fid=json['fid'],
+            valid=json['valid'],
+            template=codecs.decode(json['template'],'hex')
+        )
+    def json_pack(self): #packs for json
+        return {
+            "size": self.size,
+            "uid": self.uid,
+            "fid": self.fid,
+            "valid": self.valid,
+            "template": codecs.encode(self.template, 'hex').decode('ascii')
+        }
+
+    def __eq__(self, other):
         return self.__dict__ == other.__dict__
-    
+
     def __str__(self):
         return "<Finger> [uid:{:>3}, fid:{}, size:{:>4} v:{} t:{}]".format(self.uid, self.fid, self.size, self.valid, self.mark)
 
diff --git a/zk/user.py b/zk/user.py
index 7a5fbe6..8c7da46 100644
--- a/zk/user.py
+++ b/zk/user.py
@@ -10,7 +10,20 @@ class User(object):
         self.password = str(password)
         self.group_id = str(group_id)
         self.user_id = user_id
-        self.card = card # 64 int to 40 bit int
+        self.card = int(card) # 64 int to 40 bit int
+
+    @staticmethod
+    def json_unpack(json):
+        #validate?
+        return User(
+            uid=json['uid'],
+            name=json['name'],
+            privilege=json['privilege'],
+            password=json['password'],
+            group_id=json['group_id'],
+            user_id=json['user_id'],
+            card=json['card']
+        )
 
     def repack29(self): # with 02 for zk6 (size 29)
         return pack("<BHB5s8sIxBhI", 2, self.uid, self.privilege, self.password.encode(User.encoding, errors='ignore'), self.name.encode(User.encoding, errors='ignore'), self.card, int(self.group_id) if self.group_id else 0, 0, int(self.user_id))