If you are calling from a cellphone, and the number you are calling is on landline, you can decide what you want them to see on their call displays. If you want your call display to say it's from Grimnar, then just call the cellphone company and they will make it so.
And if they are on cellphones, all they will see is your number.
You also have the option of having your number not displayed, but most indy SPs will not answer the phone.