Who connected the offline cash register to the online store?

Question

1C-Bitrix

Hello.
Someone connected an autonomous cash register to the store? The connection instructions say

In the field “Address of the FCE device/server” enter the address of the cash desk on the Internet. The address should look like http://xx.xx.xx.xx:4444. To work, you need to forward the checkout port 4444 to the Internet.

There is no physical access to the cash desk and never will be, the client is far away. Actually, here we are talking about port forwarding from the router to the cash register, or does the cash register itself have settings, which port does it listen to?