Today marks the beginning of the move to 10-digit dialing for local telephone calls in the 705 area code.
Fifteen months ago the Canadian Radio-Television and Telecommunications Commission announced the change would be phased in between January 15, 2011, and early March 2011.
To help users adapt to the switch, seven-digit dialing will continue to work for a few weeks.
But callers using seven numbers shouldn't be surprised if they hear a recorded message about the transition.
As of March 5 all local calls will require 705 plus the regular seven-digit number.
A new area code - 249 - will also be added to prevent the exhaustion of telephone numbers in the 705 region.
The changes do not affect the 911 and 211 specialty numbers which will continue work as they have in the past.
Some older SooToday.com readers will remember when local city calls could be made using only five digits.