<P> The introduction of overlay plans as a means to reduce the need for phone numbers to change as a result of adding new area codes meant that one geographic area could be associated with more than one area code . This is disadvantageous to new service providers as existing providers can issue numbers in the familiar area code . </P> <P> In response to pressure from carriers, the U.S. Federal Communications Commission and the Canadian Radio - television and Telecommunications Commission (CRTC) have imposed 10 - digit dialling for all local calls (even within the same area code) in the overlaid areas . The requirement has no technical basis, but carriers expected it would reduce objections from new subscribers assigned the less - desirable overlay code by inconveniencing everyone equally . Consumer groups and state regulators (the Illinois Commerce Commission and Citizens Utility Board for northwest Chicago, the NYS Public Service Commission in NYC) pushed back against the requirement with attempts at litigation, to no avail . The requirement is unenforceable against PBX vendors and voice over IP operators as the dial plan is controlled by subscriber - owned equipment, which can be configured to send seven - digit calls to the original area code . It has also failed to stop a pattern of some subscribers paying third - party resellers an artificially - high price for a number in a desirable original area code like Manhattan's 212 or Toronto's 416 . A business which advertises a main number in a random overlay which did not exist at the turn of the millennium marks itself as a newcomer, or even as someone doing business from a mobile telephone, placing it at a disadvantage against long - established local competitors who first opened their doors in an era when there was just one telephone company and one area code . </P> <P> The "1" before the area code is most often required only for actual long distance calls . Some phone systems in early overlay plan areas still do not accept a "1" before the area code for non-long - distance calls; all Canadian landlines follow this pattern . However, in the three largest US markets (New York City, Los Angeles and Chicago), the initial "1" is required even for local calls . All cellphones in North America ignore this and only require the user to dial 10 digits . </P> <P> The added dialing requirement, coupled with the need to remember which of the area's coincident area codes applied to a seven - digit local number, damaged the popularity of overlay plans, which themselves were introduced as a means to reduce the inconveniences associated with the traditional split plans . </P>

When did you start having to dial area codes