A landline number is a physical phone number that makes voice connections using wires. It is a regular phone number that relies on physical wires to enable voice calls. Before the invention of cellphones, metal or cable wires were the only means for home or business telephones to place/receive calls. A landline number is associated with a device that utilizes a network of copper wires, fiber optic cables, or the internet to transmit signals for communication. The difference between a landline and a mobile phone number lies in the signals medium. Landline numbers are often used by call centers or anyone who must stay available to callers at all times because traditional copper phone lines have their own power supply, allowing them to function normally even during a blackout. Landlines are not vulnerable to breaches and hacks, and wireless landlines cannot be wire-tapped. However, landlines have physical limitations, and cordless phones can only be used within a small area.

In summary, a landline number is a fixed phone number connected with physical wires that enables voice calls. It is different from a cell phone number, which uses radio waves to transfer voice calls.