This "exchange code protection" made it possible in some low or moderate-density areas to use seven digits to reach areas in another area code (such as Hull from Ottawa before 2006, as every Ottawa-Hull local number originally was reserved in both 613 and 819).
Numerical digit | International direct dialing | Pocket dialing | Digit Fund | Dialing for Dollars | "butt-dialing" | Pelvic digit | numerical digit | Drunk dialing | Direct distance dialing | direct distance dialing | Digit ratio | "Dialing for Dollars" |