diff --git a/pyModeS/decoder/adsb.py b/pyModeS/decoder/adsb.py
index 501fa4b..b1c8e9b 100644
--- a/pyModeS/decoder/adsb.py
+++ b/pyModeS/decoder/adsb.py
@@ -51,8 +51,8 @@ def position(msg0, msg1, t0, t1, lat_ref=None, lon_ref=None):
     (works with both airborne and surface position messages)
 
     Args:
-        msg0 (string): even message (28 bytes hexadecimal string)
-        msg1 (string): odd message (28 bytes hexadecimal string)
+        msg0 (string): even message (28 hexdigits)
+        msg1 (string): odd message (28 hexdigits)
         t0 (int): timestamps for the even message
         t1 (int): timestamps for the odd message
 
@@ -93,7 +93,7 @@ def position_with_ref(msg, lat_ref, lon_ref):
     of the true position.
 
     Args:
-        msg (string): even message (28 bytes hexadecimal string)
+        msg (string): even message (28 hexdigits)
         lat_ref: previous known latitude
         lon_ref: previous known longitude
 
diff --git a/pyModeS/decoder/bds/bds05.py b/pyModeS/decoder/bds/bds05.py
index 0b271a7..29be27a 100644
--- a/pyModeS/decoder/bds/bds05.py
+++ b/pyModeS/decoder/bds/bds05.py
@@ -11,8 +11,8 @@ def airborne_position(msg0, msg1, t0, t1):
     """Decode airborn position from a pair of even and odd position message
 
     Args:
-        msg0 (string): even message (28 bytes hexadecimal string)
-        msg1 (string): odd message (28 bytes hexadecimal string)
+        msg0 (string): even message (28 hexdigits)
+        msg1 (string): odd message (28 hexdigits)
         t0 (int): timestamps for the even message
         t1 (int): timestamps for the odd message
 
@@ -85,7 +85,7 @@ def airborne_position_with_ref(msg, lat_ref, lon_ref):
     be with in 180NM of the true position.
 
     Args:
-        msg (string): even message (28 bytes hexadecimal string)
+        msg (string): even message (28 hexdigits)
         lat_ref: previous known latitude
         lon_ref: previous known longitude
 
diff --git a/pyModeS/decoder/bds/bds06.py b/pyModeS/decoder/bds/bds06.py
index 95a96cf..81ab79d 100644
--- a/pyModeS/decoder/bds/bds06.py
+++ b/pyModeS/decoder/bds/bds06.py
@@ -12,8 +12,8 @@ def surface_position(msg0, msg1, t0, t1, lat_ref, lon_ref):
     the lat/lon of receiver must be provided to yield the correct solution.
 
     Args:
-        msg0 (string): even message (28 bytes hexadecimal string)
-        msg1 (string): odd message (28 bytes hexadecimal string)
+        msg0 (string): even message (28 hexdigits)
+        msg1 (string): odd message (28 hexdigits)
         t0 (int): timestamps for the even message
         t1 (int): timestamps for the odd message
         lat_ref (float): latitude of the receiver
@@ -89,7 +89,7 @@ def surface_position_with_ref(msg, lat_ref, lon_ref):
     be with in 45NM of the true position.
 
     Args:
-        msg (string): even message (28 bytes hexadecimal string)
+        msg (string): even message (28 hexdigits)
         lat_ref: previous known latitude
         lon_ref: previous known longitude