Satphones are easy to use. Point the hinged antenna to the sky and the phone homes-in on the satellite.  A familiar handset prompts the user with dialtone.  Fax machines or notebook computers connect directly to the phone.
 
Calls travel via satellite to a Land Earth Station (LES) which passes the call into the worldwide Public Switched Telephone Network (PSTN), complete to the destination phone number you dialed.  If that number is to a computer or Internet gateway, it enables mobile-office activities familiar to computer users.
 
Each satcom has a registration number and seperate mobile phone numbers (IMNs)for voice, fax and data.   Airtime usage is monitored at the LES.  Only outgoing calls (complete to destination anywhere in the world) are charged to the satcom user according to their service plan.
 
Anyone can call your mobile phone by dialing the area code for your satellite ocean region (i.e., 870 to 874) and your mobile number.  In that case, the caller is billed at rates determined by their long distance carrier.
 
RULES:   Some countries may restrict use of satellite communications within their borders or may require advance permission and/or license fees for operation.  The Buyer shall be responsible for obtaining any and all necessary licenses or permits, including export licenses, at the Buyer's expense.  An FCC form 422 is required if send and receive sides are both inside the USA ($35 fee to the FCC).