This device is basically an adapter that provides a computer with a network connection.This can be a wire connection or also a wireless connection.
Nowadays, every computer, laptop, tablet or smartphone (mobile) has such an adapter as an integral part of the electronics that is in the device.All motherboards of modern Pcs have one or even two network connections by default. If you want to go wireless, you still need to buy a wireless network adapter with a PC that is almost always connected to the motherboard via USB plug.
In fact, that is not a device but a function in the computer.Each computer has a ‘ chip ‘ (central processing unit or processor), memory and input/output channels. The latter you need to get something in or out of memory and be processed by the processor.
That input and output is then sent to an entry or output device.For example, a keyboard (input) or display (output). Or to a hard drive to store it there.
The connection between the central part (memory/processor) and, for example, the hard disk runs via a so-called “bus” over which the bits are sent in a certain way and packaged in a defined format.
A network, whether this is a wired Ethernet, a WiFi network, Bluetooth, 3G/4G or 5G, or old-fashioned a serial connection is actually nothing but an extension of the internal bus.
However, these different transport media have their own properties in terms of electrical signal, message format and the like.And, importantly, where a bus consists of a number of parallel jobs (so that e.g. 64 bits can be shipped simultaneously) the ‘ networks ‘ consist of connections where bits can only be sent ‘ consecutively ‘ (= serial).
And those media use a carrier wave (property of electric signals) to transport those bits.Placing a bit on a carrier wave is called modulating. This is the same as for example FM in the radio (frequency modulation) and tuning channels on your TV (OK frequency modulation).
Traditionally, a Modulator/Demodulator (modem) is placed between the internal bus and the medium.If the same modem is on the other side of the media, and both modulating and serializing are the same, the bits can be recognized there again.
All former computers had COM gates, which were intended to provide on a modem to the locking and serializing.
The COM port has been replaced by USB, Firewire, and Ethernet ports, but the principle is still the same: a modem is used that converts the bits into a medium-sized format packaged according to a protested standard.But it is and remain modems.
A switch/router is a device that has multiple modem ports, and signals that arrive on a single modem, unpack to the bits that are in it, and then pack these bits back through the modem of another port to forward.The difference is that a switch handled the extracted mouthguards as an Ethernet message, a router as IP message (IP messages are sent in Ethernet messages).
Whether you have glass, ADSL or cable, your provider’s device is actually a router that turns off your internal Wi-Fi or Ethernet signals at IP level and then, depending on the destination IP address, forwards these IP packets via another modem to the Your provider’s connection router.
If the IP packets have a destination address that is in your own IP address range, that device will act as a switch and send the Ethernet message to all ports (modems) of your internal connections, including the WiFi access point.
The answer to your question is always: modem.
From the network card with a cable to a router or switch