A phone connected to a local exchange where it is “on hook (hung up)” until taken “off hook”. Built on standard copper wire and POTS phones, they are reliable, boast good voice quality, and have the basic features you might find in a typical home phone such as hold, mute, redial, and speed dial. They may also be able to transfer calls between extensions. But their features end there. Because of their simplicity and limited potential for expansion, they are relatively inexpensive to purchase. However, analog systems, because they use less-modular hardware can be expensive to support, configure, and upgrade.