How many telephone lines are required for a burglar alarm system with a UL central station certificate?

A burglar alarm system with a UL central station certificate does not require any specific number of telephone lines to be functioning. The UL (Underwriters Laboratories) standard is focused on ensuring that alarm systems meet certain reliability and performance criteria, but it does not dictate a mandatory number of telephone lines.

It's important to recognize that modern alarm systems can utilize various forms of communication to transmit signals to the central station, such as cellular networks, internet protocols, or even encrypted radio signals, which do not rely on traditional telephone lines. Therefore, the minimum requirement for telephone lines can effectively reach zero in many contemporary alarm setups, particularly those leveraging wireless technology.

This flexibility allows for more robust and diverse system configurations while still adhering to the UL certification requirements.