Length of the Unlock Code for Fido

I bought a Sierra Aircard 763S hotspot in 2014, and tried to get a unlock from Fido recently. The unlock code provided by Fido is a 12 digits number which I expected the code should be a 8 digits long base on the information from Netgear community. Anyway, I gave a try by using a non-Fido sim card in my Aircard, and went through WebUI (192.168.1.1) to key in the unlock code, it only allowed 8 digits in the input box, I keyed in the first 8 digits, it did not work. So I keyed in the 12 digits code and ignoring the box size limitation, it still did not work.

I called Fido again, re-confirmed the unlock code and asked them why the unlock code was not 8 digits long, the agent told me to check with Aircard manufacturer. The manufacturer of my Aircard was Sierra Wireless, and this product line was subsequently sold to Netgear in 2016.

I like to confirm the unlock code is 8 or 12 digits long.

If it is 8 digits, how can I get it from other source (Fido only give me 12 digits unlock code)?

If it is 12 digits, how can I key it into the box from WebUI