Unlike the mixed areas on the UK mainland, which were introduced in the 80s and 90s to deal with a shortage of codes by merging adjacent areas together, in Northern Ireland most of the exchanges were originally created as mixed areas. All these codes no longer exist as they were migrated to the new Northern Ireland Wide Area Network as part of the Big Number Change.
The set of codes beginning 0247 covered Bangor and Kircubbin. Bangor operated on the 4-digit code with 6 digit numbers and the other area added an additional digit to the code with 5 digit numbers. As part of the PhONEday changes on 16th April 1995 the codes became 01247X. However, because these areas had always existed as mixed areas, the demand for new numbers eventually exceeded the capacity of a shared code area, and that is why they migrated the whole of Northern Ireland into the new 028 range in The Big Number Change on 22 April 2000, along with Belfast which was also running out of numbers.
The codes for this mixed area are shown below with their locations. Unlike extended linked numbering scheme areas, calling between these areas required the full code to be dialled before the number. Numbers within the 4 digit 01247 code area could not start with 7 since they would conflict with the 5 digit code area.
Code |
Area |
| 01247 | Bangor |
| 012477 | Kircubbin |