On that date, almost all of the state outside Clark County, including Reno and Carson City, was assigned area code 775.Nevada's growth in the second half of the 20th century, and the corresponding expansion of telephone service, would have made a second area code a must in any event.However, the split was hastened by the proliferation of cell phones and pagers, particularly in Las Vegas, Reno, and Carson City.The split followed rumors that area code 777, corresponding to the winning number combination for some slot machines, was considered for Las Vegas.However, the telecommunications industry ruled out assigning an easily recognizable area code, so that it be reserved in the event it was needed nationally.