No that’s not what I was doing. I had a customer in Italy and the modem we used for UK was not working the same, we just had to send the command to change the modem to work for USA (Italy did not work, but I believe because there are multiple phone systems in Italy). So this has nothing to do with international calls. Any call that comes through on the line once setup properly will show, normally international calls will show as international format e.g. +44… or maybe with local dialing prefix like 0044… etc., what shows depends on the telephone company and nothing related to the modem / caller ID device.
Also please note we don’t use that modem anymore, we had issues with supply and newer models had patchy compatibility with the UK. We now use Artech USB Caller ID devices in the UK, we supply them too if you’re interested. They are a lot more stable and don’t need any country specific setup. Right now there isn’t an official integration with SambaPOS but we have modified a method another reseller used to get it working and it works perfectly, I have many clients using it now.