Which type of communicator uses RJ-45 jacks?

The correct answer is that the Internet communicator uses RJ-45 jacks. RJ-45 jacks are typically associated with Ethernet connections, which are commonly used for network communication. Internet communicators transmit alarm signals using internet protocol (IP) over a network, making use of these jacks for physical connection to the network infrastructure.

In this context, an Internet communicator can directly connect to a router or switch using standard Ethernet cabling, facilitating both the sending and receiving of data packets over the internet. This allows for alarm systems to be monitored and controlled remotely, taking advantage of the scalability and flexibility that internet communications provide.

Other types of communicators, such as analog communicators, generally rely on telephone lines and do not use RJ-45 jacks. Digital communicators may also use telephone lines or other methods, but they too are not specifically tied to the RJ-45 interface. Wireless communicators rely on radio frequencies for communication and therefore do not require any physical jacks. The Internet communicator's use of RJ-45 reflects its dependence on network-level connectivity for effective alarm system operation.