The short answer is No. Unlike "Digital Voice" or "VoIP" services from providers like BT or Sky, ONSIM Landline Replacement does not require an internet connection, a router, or any extra cabling in your home.
How it works without the Internet
Traditional digital home phones send your voice as "data" over a broadband line. ONSIM uses a different, more reliable technology:
The ONSIM SIM: Our Landline Replacement box contains a specialised ONSIM SIM card.
Mobile Voice Network: Instead of using the internet, the box connects directly to the UK’s strongest mobile voice network.
Analogue Conversion: The box takes that mobile signal and converts it into a standard "dial tone" that your existing home phone can understand.
Is it reliable?
Yes. Because our service uses the dedicated voice frequency of the mobile network (the same technology used for billions of mobile calls every day), it is often more stable than VoIP. VoIP calls can "stutter" or drop if someone else in the house is streaming a movie or if the internet speed fluctuates. ONSIM calls remain clear and consistent.
What if I have poor mobile signal?
Request a Check: If you already know that mobile signal is an issue in your home or office, please contact our support team at support@onsim.uk.
Important: When emailing, please include your full postcode. Our technicians will run a coverage report for your exact location to confirm whether the service will work reliably for you before you commit.