Landline number
Definition
A fixed-line phone number tied to a home or office connection rather than a mobile phone or SIM.
Landline number, explained
A landline number belongs to a fixed telephone service at a home or business address, delivered over copper lines, fiber or a broadband connection. Line type checks classify these numbers as landline rather than mobile or VoIP. Most landlines cannot receive SMS in the normal way, so apps that verify by text usually reject them or never deliver the code. Some providers convert texts sent to a landline into a spoken message, but that is not reliable for verification. Many platforms offer a voice call option instead, where an automated call reads the code aloud; WhatsApp Business, for example, can verify a landline this way. Landline numbers are useful for businesses that want a stable, published contact number, and for people who keep a home phone for years. For SMS verification you generally need a mobile number. Noir SMS temporary numbers are mobile numbers that receive SMS only, so they cannot take the voice calls a landline-style verification would require.
Related terms
Voice verification
Confirming a phone number by answering an automated call that reads you a one-time code.
Line type lookup
A check that tells an app whether a number is mobile, landline or VoIP, and often which carrier owns it.
Area code
The digits after the country code that indicate a geographic region, like 212 in the US or 20 for London.