Bizarre router password behaviour

[#1]

I am confused and wonder if anyone could explain this.

I have a friend visiting my house with a French laptop which of course has a French keyboard - it is AZERTY instead of QWERTY.

When he tried logging into my router, the password kept failing.  So I had a go, and it also failed.  Eventually, I thought I would be stupid and try to use the UK letters for the French letters (no pun intended !).  So instead of "Q" on his keyboard, I entered "A"; and instead of "M" on his keyboard, I entered "?".  Amazingly, it worked.

Now what I cannot understand is that surely, when you press any letter, it is the ASCII code which is sent irrespective of the hardware.  So why does ASCII for "Q" get sent instead of "A" and "M" instead of "?"  ?

I would understand if Windows was set to use the UK keyboard instead of the French keyboard but that is not the case.  It is set for the default French keyboard.  I can only imagine that somehow the router (BT Homehub 5) is not responding to ASCII but to something else.

The problem is sorted, and the router can be accessed.  As a last resort, I could of course have used the WPS button.  But I am still curious to know why this is happening.

[#2 · Accepted solution]

Not at all sure about this, but might it be that HEX codes rather than ASCII are used by the router and that these are being sent by the keyboard? It is certainly possible to enter a password in HEX, although it is of course much longer than the ASCII equivalent.

[#3]

It could be the case but it still seems odd that the keyboard should send a different HEX code letter than it sends in ASCII.  On the other hand, maybe keyboards have fixed HEX codes and Windows interprets the HEX code, and reads the HEX code and then customises the keys by software to suit the various languages using ASCII.  I wonder if anyone else has come across this ?  If the router is responding only to the original HEX code, then that would explain it, but it would mean that the same problem would be encountered with any foreign language.

[#4]

Don’t you mean scan codes as opposed to HEX here, as this makes no sense as HEX is simply a number base and the values, regardless of language, are the same after all it is ASCII which is a standard.

However if the key at UK position A send a Q or vice versa then this must be down to the scan code being used, other wise all keyboards in the world not English would need to be physically different. But as you know you can change the layout of any keyboard by changing its type and mapping, where the character displayed depends on the mapping used.

[#5]

You are probably correct.  I am not technical ! It does make more sense if there are scan codes which I did not know that there are.  I assumed that each key was assigned an ASCII code which was then sent to the router, but if there are scan codes - presumably one code for each physical key position, regardless of the letter assigned to it - that would make a lot of sense.  If the router password is really looking for a physical key position (i.e. a scan code) and not for a particular letter, then it would explain it.

However, this cannot be an issue unique to my French friend with his French laptop.  I take my laptop all over the world, and signing in to other routers should cause me the same problem in theory when I am in a country that does not use QWERTY, but I have never encountered it before.  The only explanation that I can think of is that the BT Homehub 5 is an exception and looks for scan codes whereas other routers look for ASCII.

[#6]

Any key on an American / European keyboard generates what is called a scan code, the same code will be generated on all keys on all keyboards, but the actual character generated when a given key is pressed is dependent on the keyboard type and locale associated with it.

If you’ve ever installed any Operating Systems like Windows or Linux you may recall being asked what kind of keyboard you have and what language you use, this is so that the software can install the correct drivers to map the keys correctly.

[#7]

That explains it perfectly.  Thanks.