When referring to traditional "landline phone alarm monitoring", this communication path utilizes a circuit switched telephone that uses a solid core, twisted pair copper wire, and plugs into a two or four pin wall jack. There a few alarm industry abbreviations often used for sending alarm signals over the traditional phone line, such as plain ordinary telephone services "POTS" and public switched network "PSTN".
Over the past 100 years, the copper wire phone technology has not changed too. Traditional landline phones are based on an analog technology which transmits signals through a series of exchanges and physical switch boxes that connect calls between two phones.
Although this hardwired copper technology is very old, it is ironically very reliable. Because landline phones use physical wire connections to make and receive calls, they aren't as susceptible to the service interruptions and slowdowns of other services. However, they are susceptible to deliver line cutting and/or tampering.
The negatives of landline phone are that the wiring is very labor intensive, confusing, and it takes up alot of space. So, the Federal Communications Commission "FCC" is passing new legislation against traditional landlines and recommending consumers to ditch their landlines.