diff --git a/lasp/device/lasp_device_common.py b/lasp/device/lasp_device_common.py
index 1ad2cec..cbc54eb 100644
--- a/lasp/device/lasp_device_common.py
+++ b/lasp/device/lasp_device_common.py
@@ -1,12 +1,13 @@
 __all__ = ['DaqChannel']
-from ..lasp_common import Qty, SIQtys
+import json, logging
 from dataclasses import dataclass, field
-from dataclasses_json import dataclass_json
 from typing import List
-import json
+from dataclasses_json import dataclass_json
+from ..lasp_common import Qty, SIQtys
+
 
 @dataclass_json
-@dataclass
+@dataclass(eq=False)
 class DaqChannel:
     channel_enabled: bool
     channel_name: str = 'Unnamed channel'
@@ -17,12 +18,12 @@ class DaqChannel:
     channel_metadata: str = ''
 
     def __post_init__(self):
+        # logging.debug(f'__post_init__({self.channel_name})')
+        self._qty = SIQtys.default()
         if len(self.channel_metadata) > 0:
             meta = json.loads(self.channel_metadata)
-            if '_qty' in meta:
-                self._qty = Qty.from_json(meta['_qty'])
-        else:
-            self._qty = SIQtys.default
+            if 'qty' in meta:
+                self._qty = Qty.from_json(meta['qty'])
 
     @property
     def qty(self):
@@ -31,7 +32,7 @@ class DaqChannel:
     @qty.setter
     def qty(self, newqty):
         self._qty = newqty
-        self._store('_qty', newqty)
+        self._store('qty', newqty)
 
     def _store(self, name, val):
         if len(self.channel_metadata) > 0:
@@ -42,3 +43,15 @@ class DaqChannel:
         meta[name] = val.to_json()
         self.channel_metadata = json.dumps(meta)
 
+    def __eq__(self, other):
+        """
+        We overwrite the default equal-check as the floating point values
+        cannot be exactly checked due to conversion from/to JSON
+        """
+        return (self.channel_enabled == other.channel_enabled and
+                self.channel_name == other.channel_name and 
+                self.range_index == other.range_index and 
+                self.ACCoupling_enabled == other.ACCoupling_enabled and 
+                self.IEPE_enabled == other.IEPE_enabled and 
+                self.channel_metadata == other.channel_metadata)
+
diff --git a/lasp/lasp_common.py b/lasp/lasp_common.py
index 9b152ec..3ce3c3d 100644
--- a/lasp/lasp_common.py
+++ b/lasp/lasp_common.py
@@ -1,8 +1,5 @@
 # -*- coding: utf-8 -*-
-import os, platform
-import shelve
-import sys
-import appdirs
+import shelve, logging, sys, appdirs, os, platform
 import numpy as np
 
 from .wrappers import Window as wWindow
@@ -59,21 +56,36 @@ class AvType(Enum):
 
 
 @dataclass_json
-@dataclass
+@dataclass(eq=False)
 class Qty:
     name: str
     unit_name: str
     unit_symb: str
-    level_unit: str
-    level_ref_name: str
-    level_ref_value: str
+    level_unit: object
+    # Contains a tuple of possible level names, including its reference value.
+    # For now, it is only able to compute for the first one. I.e.e we are not
+    # yet able to compute `dBPa's'
+    level_ref_name: object
+    level_ref_value: object
 
     def __str__(self):
-        return self.name + f' [{self.unit_symb}]'
+        return f'{self.name} [{self.unit_symb}]'
+
+    def __eq__(self, other):
+        # logging.debug('eq()')
+        """
+        Comparison breaks for the other objects, level unit, level ref name,
+        etc as these are tuples / a single string.
+
+        """
+        return (self.name == other.name and
+                self.unit_name == other.unit_name)
 
 
 
-class SIQtys:
+
+@unique
+class SIQtys(Enum):
     N = Qty(name='Number',
             unit_name='No unit / full scale',
             unit_symb='-',
@@ -96,9 +108,6 @@ class SIQtys:
              level_ref_name=('1V',),
              level_ref_value=(1.0,),
            )
-    types = (N, AP, V)
-    default = N
-    default_index = 0
 
     @staticmethod
     def fillComboBox(cb):
@@ -109,20 +118,18 @@ class SIQtys:
             cb: QComboBox to fill
         """
         cb.clear()
-        for ty in SIQtys.types:
-            cb.addItem(f'{ty.unit_name}')
-        cb.setCurrentIndex(SIQtys.default_index)
+        for ty in SIQtys:
+            cb.addItem(f'{ty.value.unit_name}')
+        cb.setCurrentIndex(0)
+
+    @staticmethod
+    def default():
+        return SIQtys.N.value
 
     @staticmethod
     def getCurrent(cb):
-        return SIQtys.types[cb.currentIndex()]
+        return list(SIQtys)[cb.currentIndex()]
 
-    @staticmethod
-    def getIndex(qty):
-        for i, qtyi in enumerate(SIQtys.types):
-            if qtyi == qty:
-                return i
-        return -1
 
 @dataclass
 class CalSetting: