About Open Line
Open Line publishes practical guides to the ways people make calls today: VoIP apps, carrier Wi-Fi calling, VoLTE, eSIMs, roaming and international calling.
The audience is ordinary users rather than telecom engineers: travellers, people with family in another country, small teams choosing a calling app, and anyone who wants to know why a call dropped or what a "Wi-Fi call" on their bill means.
How the guides are written
- Every rule, figure or technical claim is checked against a primary source: EU regulations on EUR-Lex, regulator pages (European Commission, BEREC, FCC, Ofcom), IETF and ITU standards, or the official documentation of the platform concerned.
- Where a figure depends on the app, the carrier or the country, the guide says so instead of quoting a single number.
- Calculations (for example the data used by a call) show their working, so you can redo them with your own values.
- Guides are reviewed when rules change, and the date of the last update is shown at the top of each page.
What Open Line does not do
Open Line does not provide a calling service, accounts, top-ups or price plans, and it does not take payment for recommendations. Brand names are mentioned only to describe how a product works; trademarks belong to their owners.
About this domain
In the early 2010s this domain hosted VikingTalk, a smartphone VoIP calling service aimed at users in Belgium, with pages in Dutch, French and English. Several years later, from around 2021, the domain carried an unrelated multi-topic blog. Open Line is a new, independent publication: it has no connection with the VikingTalk service, the companies behind it or the later blog, it does not offer their products, and none of their texts or images are reused here. Old account and sign-in addresses on this domain no longer exist.
Corrections
Rules on roaming, emergency calls and number porting change. If you spot an outdated or wrong statement, corrections are welcome; the publisher's details are in the legal notice.