What is a special device that is installed in your computer and allows it to communicate with other devices on the network?

That would be the network card or modem.

NIC (Network Interface Controller)

network interface card

There are multipule answers to this question. 1.) A Monitor (Visual Commuication) 2.) Speakers (Verbal/Vocal Communication) 3.) Keyboard (Input Device) 4.) Mouse (Input Device)

usally Firewalls config for comunicate to another networkFirewall located in edge of network,firewall is a roter or a pc with a special software.