How can i use the phone in GTA IV? When i press the UP Arrow there's no numbers written on the screen, i think that mobile is Iphone 8?

How can i use the phone in GTA IV? When i press the UP Arrow there's no numbers written on the screen, i think that mobile is Iphone 8?

I think you have to pass either 2 or 3 missions b4 you can get acces to it. Then it's up