Sally's cordless phone base is plugged into the phone port of her OBi. Her mom also has an OBi so Sally calls her mom OBi to OBi (a 9 digit number).
If her mom has an OBi110 hooked up to a standard phone line through a telco, Sally can call OBi to OBi and then have her mom's OBi bridge a call over the telco line to any telephone number. So Sally can call her mom's OBi from Europe to the US and have her mom's OBi bridge her call to any US number for free (i.e. Larry).
Of course, there's a lot more you can do with it. The OBiApp/OBiON is for PCs, cell phones, ipods, ipads, etc. to connect to an OBi over the internet/wifi (data not cell minutes)