Phone prefixes in Durham, ON

In numbers

In-service prefixes

11

Telephone numbers covered

110,000

Carriers

7

Area codes

3

Provinces and territories

1

First assignment

July 19, 2000

Most recent assignment

September 18, 2024

Durham’s share of its area codes

Within area code 226, Durham accounts for only 5 of 778 prefixes (0.6%): the code is dominated by London and spread over 166 rate centres. Within area code 519, Durham accounts for only 3 of 779 prefixes (0.4%): the code is dominated by London and spread over 210 rate centres. Within area code 548, Durham accounts for only 3 of 499 prefixes (0.6%): the code is dominated by London and spread over 170 rate centres.

Who holds these numbers

Iristel Inc. holds the largest share at 4 prefixes, 36.4% of the total, ahead of 6 other carriers. Code by code: in 226, Iristel Inc. leads with 2 of 5 prefixes ahead of 3 others; in 519, Bell Canada leads with 2 of 3 prefixes ahead of 1 others; in 548, Iristel Inc. leads with 2 of 3 prefixes ahead of 1 others. No carrier holds prefixes in every one of Durham’s 3 area codes, while 6 appear in just one.

Wireless and wireline

1 of Durham’s 11 prefixes (9.1%) are held by carriers whose registered name marks a wireless business: Bell Mobility. Wireline prefixes still outnumber them, carried by Iristel Inc, Bell Canada, Bragg Communications Inc and Fibernetics Corporation. This is a sort by name, not a licence lookup, and a mobile prefix may have been ported to another network since.

How the allocation was built up

Durham’s dated assignments run from 2000 to 2024. The busiest period was 2015–2019, when 3 prefixes went to 2 carriers. 1 prefixes (9%) carry no date in the register: these are the historic pre-1999 assignments, the wireline bedrock of the rate centre. Since 2020 another 3 prefixes have been added, so the rate centre is still growing.

Durham’s oldest prefixes, the ones the register leaves undated, belong to Bell Canada: this carrier made up the landscape before competition arrived. The first dated assignment went to Bell Canada in 2000. The most recent arrivals are Wightman Communications Ltd. (2021), TELUS Integrated Communications (2017) and Iristel Inc. (2016), a sign that new carriers are still asking for numbers in Durham.

Durham has only 11 prefixes, or 110,000 numbers: a small rate centre, where the arrival of a single new carrier visibly changes the landscape.

No single carrier dominates Durham: the leader, Iristel Inc., holds only 36.4% of the prefixes against 6 competitors, a sign of a highly fragmented market where cable companies, mobility brands and VoIP providers weigh as much as the incumbent.

Demand remains steady: 30.0% of the dated prefixes go back to the last ten years, the most active period being 2015–2019. The rate centre is growing at a regular rather than explosive pace.

1 undated in the register.

Dialling a Durham number

Durham is served by 3 overlaid area codes (226, 519 and 548). A 548 number is no more “out of town” than a 226 one; from abroad, dial +1 and the full ten digits.

The numbering neighbourhood

Durham shares area codes 226, 519 and 548 with at least 20 other rate centres, including London, Kitchener-Waterloo, Windsor, Guelph, Brantford, Sarnia, Chatham and Hespeler. The largest of them, London, holds 214 prefixes in 226, 519 and 548; the smallest on the list, Essex, has just 16.

What a Durham number tells you

A number attached to Durham tells you that its prefix was issued to a carrier for this rate centre in Ontario, most often Iristel Inc.. It does not tell you where the handset is today: a subscriber may have ported the number to any of the 7 carriers present here or to a VoIP service usable anywhere. Nor does it tell you who is calling: caller ID can be spoofed, and an Ontario area code is easy to borrow to look local.

Reading a register entry for Durham: code 226-702 is recorded for Iristel Inc., so every 226-702-XXXX number (10,000 possible) descends from that assignment. “Durham, Ontario” there names a rate centre, not a municipality, and several area codes overlay it.

Every Durham prefix

Each row is an in-service central-office code recorded for Durham, with its original holder and year of assignment.

Allocated prefixes

All 11 in-service prefixes, grouped by rate centre.

Elsewhere in Ontario