|Device||What is does|
|Gateways:||Convert information from one format to another.
|Modem:||Stands for modulating demodulating.
They allow devices to communicate with other remote devices by converting digital data into analog data and transmitting it over an analog telephone line.
|Routers:||Are responsible for sending data from one network to another.|
|Switches:||They use the MAC address of a device to send data only to the port the destination device is plugged into.|
|Hubs:||Unlike switches, hubs broadcast data to all ports, which is inefficient.|
Note: modern voice system will require your network to have a router in it. Despite the fact that some modems have integrated router features, they barely capable of maintaining voice systems functionality. You may want to have both modem and router in your network (modem will need to be launched in bridged mode).