diff --git a/Commands.md b/Commands.md
index 68a604d..079d35d 100644
--- a/Commands.md
+++ b/Commands.md
@@ -23,13 +23,13 @@ Given we use I2C for comms using hex as the commands are reasonable.
 | 0x02 | Fan 2 |
 
 ## Read commands
-| command | description | parameter |
-| :-- | :-- | :-- |
-| 0x11 | Read config | |
-| 0x12 | Read voltage | Volage source |
-| 0x13 | Read temperature | | 
-| 0x14 | Read current fan speed | Fan number |
-| 0x15 | Read bulk fan speed | Fan number |
+| command | description | parameter | read length |
+| :-- | :-- | :-- | |:-- |
+| 0x11 | Read config | | ? |
+| 0x12 | Read voltage | Volage source | 2 | 
+| 0x13 | Read temperature | 2 | 
+| 0x14 | Read current fan speed | Fan number | 2 |
+| 0x15 | Read bulk fan speed | Fan number | 2 * num |
 
 ## Write commands
 | command | description | parameter |