Phone prefixes in Castlemore, ON

In numbers

In-service prefixes

18

Telephone numbers covered

180,000

Carriers

13

Area codes

4

Provinces and territories

1

First assignment

December 8, 2000

Most recent assignment

October 27, 2023

Castlemore’s share of its area codes

Within area code 365, Castlemore accounts for only 8 of 702 prefixes (1.1%): the code is dominated by Markham and spread over 88 rate centres. Within area code 905, Castlemore accounts for only 5 of 773 prefixes (0.6%): the code is dominated by Hamilton and spread over 94 rate centres. Within area code 289, Castlemore accounts for only 3 of 772 prefixes (0.4%): the code is dominated by Hamilton and spread over 87 rate centres. Within area code 742, Castlemore accounts for only 2 of 146 prefixes (1.4%): the code is dominated by Brampton and spread over 68 rate centres.

Who holds these numbers

Rogers Communications Canada Inc. (Cable) holds the largest share at 3 prefixes, 16.7% of the total, ahead of 12 other carriers. Code by code: in 365, Fibernetics Corporation leads with 2 of 8 prefixes ahead of 6 others; in 905, Rogers Communications Canada Inc. (Cable) leads with 3 of 5 prefixes ahead of 1 others; in 289, Distributel leads with 1 of 3 prefixes ahead of 2 others; in 742, Beanfield Technologies Inc. leads with 1 of 2 prefixes ahead of 1 others. No carrier holds prefixes in every one of Castlemore’s 4 area codes, while 12 appear in just one.

Wireless and wireline

None of Castlemore’s holders carries a mobility brand in its registered name: all 18 prefixes belong to wireline or wholesale carriers, among them Rogers Communications Canada Inc. (Cable), Bell Canada, Distributel and Fibernetics Corporation. A call showing a Castlemore number therefore nominally comes from a landline, cable or VoIP platform rather than a locally assigned cellphone.

How the allocation was built up

Castlemore’s dated assignments run from 2000 to 2023. The busiest period was 2020–2024, when 6 prefixes went to 5 carriers. 1 prefixes (6%) carry no date in the register: these are the historic pre-1999 assignments, the wireline bedrock of the rate centre. Since 2020 another 6 prefixes have been added, so the rate centre is still growing.

Castlemore’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 Rogers Communications Canada Inc. (Cable) in 2000. The most recent arrivals are FGLTEL Inc. (2022), Beanfield Technologies Inc. (2021) and TekSavvy Solutions Inc (2020), a sign that new carriers are still asking for numbers in Castlemore.

Castlemore has only 18 prefixes, or 180,000 numbers: a small rate centre, where the arrival of a single new carrier visibly changes the landscape.

No single carrier dominates Castlemore: the leader, Rogers Communications Canada Inc. (Cable), holds only 16.7% of the prefixes against 12 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: 35.3% of the dated prefixes go back to the last ten years, the most active period being 2020–2024. The rate centre is growing at a regular rather than explosive pace.

1 undated in the register.

Dialling a Castlemore number

Castlemore is served by 4 overlaid area codes (365, 905, 289 and 742). A 742 number is no more “out of town” than a 365 one; from abroad, dial +1 and the full ten digits.

The numbering neighbourhood

Castlemore shares area codes 365, 905, 289 and 742 with at least 20 other rate centres, including Hamilton, Brampton, Oshawa, St. Catharines-Thorold, Oakville, Markham, Ajax-Pickering and Cooksville. The largest of them, Hamilton, holds 221 prefixes in 289, 365, 742 and 905; the smallest on the list, Dunnville, has just 28.

What a Castlemore number tells you

A number attached to Castlemore tells you that its prefix was issued to a carrier for this rate centre in Ontario, most often Rogers Communications Canada Inc. (Cable). It does not tell you where the handset is today: a subscriber may have ported the number to any of the 13 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 Castlemore: code 905-200 is recorded for Rogers Communications Canada Inc. (Cable), so every 905-200-XXXX number (10,000 possible) descends from that assignment. “Castlemore, Ontario” there names a rate centre, not a municipality, and several area codes overlay it.

Every Castlemore prefix

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

Allocated prefixes

All 18 in-service prefixes, grouped by rate centre.

Elsewhere in Ontario