How to Dial plus sign on home phone?

The "+" indicates that the telephone is an international number, and you need to find out what the international dialling code is for your country.

For example, the innerational dialling code for most European countries is "00", while in the US, it's "011". Therefore to dial a +44 number, from the US, you would dial 011-44 etc and from EU you would dial 00-44 etc.

If you are calling a UK (+44) from within the UK, you drop the +44 and dial a 0 instead, as you don't need to access the internationl telephone network.

As mobile phones have login built into them, they can work this all out for themselves, while most landlines have no logic, and will dial out exactly what you tell it to.