See is the firmware supports VOIP, then that socket should take a phone but won't use the sim cards minutes.

I also have a H112-370 and unfortunately I can't make or receive calls using the sim from three. I was hoping it would at the very least support VOLTE to make calls even if it can't drop down from 4G/5G to 3G but no such joy as it doesn't even have the VOLTE page.

Hoping usual forums will come up with a flashable firmware which supports VOLTE but they still haven't found the points for the USB TTL cable

Out of interest where did you get the router from. Three? Voda? China? There’s limited sources which seems a shame for what looks like a pretty top sites router. Even for 4g there’s little else around with all the UK bands and 3ca or above plus 4x4

If you can get the internet through RJ5, you can log into the web interface and reset the WiFi password yourself.

Actually, the Huawei 5G CPE Pro H112-370 is not better than the H112-372, which has the original firmware and no customization.

Shove a paperclip in the reset hole on the router and just use the WiFi password on the sticker on the router.

On my Huawei B525 router I (foolishly) did a factory reset using the reset button.
After that it would neither accept the admin login password I had been using nor the one written on the device.
Then I tried using the Huawei app to log in, That worked, and I was able to set a suitable password.