provincial border; all federal government offices on the Quebec side duplicated several exchanges worth of their counterparts on the Ontario side. Rapid growth Urban sprawl accelerated the rate of expansion of metropolitan areas, and multiple split plans have caused the geographical area of a given area code in those regions to shrink, except in countries that assign shorter area codes and longer local numbers in areas with high population densities. The rapid growth in popularity of electronic devices (pagers and then mobile phones), in addition to regular landline growth, increased demand for new phone numbers even more. Although landline growth has sharply dropped and even decreased, largely by the elimination of residential landlines in favor of personal mobile phones, it has been replaced by the even worse problem of data-only devices (hotspots, modems, netbooks, and especially popular tablets), which still require a telephone number for use on cellular networks even if they are unable to make or receive regular calls. The rise in popularity of mobile devices has added to the pressure against split plans, as an area-code change affecting the exchange in which a cellphone is based not only forces customers to reprogram their phones but also requires the wireless carrier to reassign the number of every device based in those areas. While phones with a SIM card have their own mobile device number updated automatically, there is still the inconvenience of users having to update their contact lists for local family members or others who have had their numbers changed too. Compromise Most overlay plans introduced the inconvenience of mandatory ten-digit dialing in which the area code must always be included even for local calls. Ten-digit dialing is not a technically necessary requirement, and 917 was initially deployed without it, but a US Federal Communications Commission (FCC) mandate instituted it at the demand of major telephone companies, to whom an overlay is considered a disadvantage to competitors. In Canada, ten-digit dialing is also a requirement of the Canadian Radio-television and Telecommunications Commission in overlay area codes. Popularity Overlays were initially met with resistance, as they result in multiple area codes in the same geographic area, which requires ten-digit dialing. In many cases, such as 847 in Chicago's northwestern suburbs and 212 in New York City, an overlay was an additional disruption to a community that had already been subject to one or multiple code splits, encountering pushback from