Xperia XZ Bluetooth pairing pin code 16 digits?

[Pepe84]

Dear Xperia Support,

I have a new Xperia XZ phone with latest Oreo 8.0 updating.
Version: 41.3.A.2.24

I not use Bluetooth till now...but now I try to connect to an Bluetooth serial adapter (HC-06)
My old Xperia S (Android 4.1.2) or other  mobile request 4 digits pairing pin code: 1234

...and works well...

But now this phone request 16 digits...4 pcs not enough, not appear the "OK" button.
So... i can't making pairing.

I try
1234000000000000  

or

0000000000001234   code but not work.

I made Factory reset too... but same situation.

Why request 16 number instead of 4 pcs?
How possible to solved?
Please check the below picture:

Thank you very much your support.

[Pepe84]

Ahh  I found the soulution:

The Bluetooth adapter no has name, it was empty...

After I give name (AT commands)... the Xperia XZ can indentify the BT adapter, and appear 4 digits pin code.

So it is ok
...but i not understand other Android system why can indentify automatically...

Thanks bye

[critta]

Hi pepe, I have been experiencing this problem with my car. On my android orea it only shows the 16 digit bluetooth mac address. and it wont let me connect.. My car gives a 4 digit pin and just like you the phone wants a 16 digit pin. anyway that aside.

can you tell me how you named your device you were connecting to using at commands. Or even just point me in the right direction.

will be very much appreciated thank you

Cheers Jeff