This page deals with networking hardware in the context of vintage computing. It's going to also be including a lot of MODERN elements because when you are connecting a computer to the internet, or a network today, it's going to involve working with much newer things like Internet Security, network security, Routers, Gateway "cable modems", and other stuff that a person who may not be all that interested in the "modern" technology, might be interested in.
Modern computer networks in the home are TCP/IP based networks that connect to the internet through a gateway, and use a Wireless Access Point (WAP) and/or a Router to direct traffic to and from the internet, as well as allow all the devices in the house to talk to each other over WiFi or wired "Ethernet". Let's tart at the ISP on back...

ISP - aka your Internet Service Provider, this is Charter, Spectrum, Comcast, etc. They have a "node" most likely in your town that everything connects to and can access the internet from. To allow you to do this, the ISP usually provides you a "secure gateway" otherwise referred to usually as a "Modem" (a total misnomer TBH) that you'll most likely pay a monthly fee for. You pay them the agreed costs per month, they don't shut off your Gateway's access to the internet. That's how it works. Sometimes they have extra perks like web-hosting, e-mail addresses, domains, and whatnot, but overall, the ISP's only role is to enable their network to allow your Gateway to get on it and access the internet through it.

Typically this signal chain is ISP - Gateway/Modem - then maybe the computer itself, or a router and wireless acces point. Sometimes the functionality of these three core elements are combined.

Vintage Computers still use much the same technologies as modern PCs do in the networking space on the hardware end. They still use RJ-45 connector based ethernet cables to connect all wired clients/devices, and they are all capable of connecting to a TCP/IP (Transmission COntrol Protocol/Internet Protocol) network. More on that later.
So let's take a look at these devices and what they are, and how they work in the context of Network traffic a little bit....
Internet Service Provider
The internet Service Provider is the company which you pay for access to the internet through. Without one, you won't have internet access (at least, not legally). Different ISPs employ different technologies depending on your region. The most popular right now are "Broadband" which use Cable (like we used to use for Cable TV) such as Charter or Spectrum, or Fiberoptic Networks (Fiber) such as AT&T. Some companies that may still offer Landline service may offer Dial-Up still over the old copper telephone lines, or even DSL. They charge you a monthly fee to use their network - usually between $15-300 a month depending on if they bundled a bunch of Cable TV shit to your account or not (and no, it's not saving, no matter what the sales schmuck on the other side says). The "point of demarcation" - ie the points that the ISP covers regarding your internet connection, is anything in their buildings, and the gateway and provided hardware. Anything else you use is your own problem, generally. So keep that in mind. THey have no Juristiction over any routers, WAPs, or other stuff you purchased, and I'd be a bit weary of any attempts to let them manage that stuff (I'm looking at you AT&T ActiveArmor).
The Classic Dial-Up Modem is a serial device that uses old school POTS Landline PBX Analog Telephone system to "dial up" to another modem on the other end for communication. These have been in use since the 1970's, and are generally considered Obsolete. Most Dial-Up ISPs work by having a modem at the other end that you can access using "Local Area Access Numbers" - usually a group of phone numbers the ISP has ownership of, that will let your computer connect to their "Node" on the internet for access. Dial-Up can range in speeds from 300baud to 56K V.92 standard speeds, and compared to modern "Broadband" connections, are considered VERY slow. But people still use Dial-Up for specialized purposes like Faxes or if you live somewhere rural where Broadband may still not be an option, such as being a Farmer in the middle of bumfuck nowhere Wyoming, Montana, or Idaho - or maybe the middle of hte Nevada desert - out of reach of a broadband provider. I mention it because people forget about these outliers when it comes to the modern internet and I feel like they are being left behind as a result. What a modem does, is it transforms the digital output of your computer to an analog phone signal (ie, all that screeching, beeping, and white noise you'd get picking up the phone when someone was on the internet in the 1990's), and then the modem on the other end put's it back together as a digital signal via modulation - ie it Modulates and Demodulates signals ie MoDem! Modems typically came in "External" style which attached to the 25-pin Serial Port on your computer, or "internal" that used the ISA/PCI Bus inside the computer to control it. Beware though, as the 90's went on, late model modems were often dubbed "Winmodems" because much of the Modem's functionality was reliant on Microsoft Windows's performing it in software vs. the modem doing all the work as a classic modem did. The oldest modems - Acoustic Coupler Modems - required actually putting a bloody Telelphone handset INTO The modem to use it, lol.
DSL is called a "Digital Subscriber Line" and works roughly similiar to modern Broadband more than it does old-school Dial Up. Basically, your DSL "Modem" connects to your copper landline connection full time, as opposed to having to dial up a local area access number every time. The DSL "modem" connects the same as a regular Landline modem, and then the computer connects to it via an Ethernet Cable - rather than as a ISA/PCI expansion card or a external device over a Serial Port. Usually these were leased/rented/sold to you by your Internet Service Provider - Frontier Networks (originally Verizon) being one of them. These could range from 150Kbps all the way to around 768Kbps or more.
(Optical Network Terminal)
This is one way to tell if you have Fiber Broadband, or Cable Broadband, is the presense of a ONT in your dwelling. The ONT provides a Fiberoptic connection to the ISP over Fiber Optic Line, and then connects to your Gateway via Ethernet cable. Fiber Optic network connections use pulses of light over fiber-optic line rather than electrical on/off pulses to represent the 0's and 1's that constitute binary data. This is required to translate the Fiber network's light signals to something Ethernet can understand. This is something you should not have to deal with at all as a Fiber subscriber, as the ISP does the installation and handles it for you.
(Often Called a "Modem" but it's not)
This is what most of us have in our suburban and urban homes today, the ubiqutous "Modem" or "Cable Modem" or "Fiber Modem" - these devices are not really "modems" but rahter "Secure Gateways" intended to allow traffic to enter an ISP over the internet - almost like it's own node that the ISP can remotely turn off the connection to. This is also referred to as "Broadband" because it can use higher frequencies, and therefore can move more data around much faster. They typically use one of two technologies: Fiber (Which requires an ONT at the user site), or Cable (the old Coaxial Cables you used for Cable TV and connecting your Nintendo to the TV via RF back in the day). The ISP does most of the work on this for you, but you have some ways of tweaking it. Throughput is in the Megabits per second, instead of Kilobits. 300Mbps is considered "Basic" these days, while some of these can be as fast as a Gigabit or more.
Sometimes Built into the Gateway and even combined with a WAP)
A Router is a device that routes internet traffic to and from "the internet" (actually your modem or secure gateway) when several devices are attached. Originally, ISPs only allowed for ONE device on your in-home network (usually a wired desktop PC), and to attach more devices, you had to purcahse one from your ISP and pay a monthly fee for it in some cases. Or you could buy an external one at home, "Spoof" the MAC Address (Medium Access Control Address is what it stands for) of the NIC on your "primary" computer so that your ISP and the internet only see that device and not the 2+ devices behind it, though more and more in recent years, ISPs are providing a Router BUILT INTO the Secure Gateway, removing the need for external hardware to expand it. Most of these devices have visible statistics that can be seen at a default IP Address you can type into a web browser, and possibly even the ability to reboot the Router or change certain settings. This is device/ISP dependant. It is also possible with most ISPs to purchase your own Secure network Gateway from a place like Best Buy or Amazon and then register it with your ISP to connect to their network with it (though some may have an *approved* list). Most routers are user-editable by typing in a or 192.168.254 IPv4 Internet address into a web browser to change settings. This goes the same with your ISP's secure gateway router WAP combo devices.
(Wireless Access Point)
Let's just forget Cardi.B exists - WAP Stands for WIRELESS ACCESS POINT and it is how your laptops, Cellular Phones, Game Consoles, Smart-devices/IoT stuff connects to the internet in your house over WiFi. Originally, these were a separate little box you hung on a ceiling or sat up high on a dresser somewhere, and connected through your internet router. Some Routers come with a WAP installed inside of it that you can control via the Router's firmware. Other Access Points have their own IP and need to be configured independantly. Wireless Access Points provide network access over a SSID (Service Set Identifier) which is basically the funny little names that pop up when you look for WiFi Networks on your wireless devices like "2guys_In_A_Boat" or "IRS_Surveillance_Van_04" or "Put_ur_SSN_Here" or "MyCharterWiFi_69-5G". These almost always have some form of security these days, even the open ones. In-Home should use WPA or WPA-2 PSK (Wireless Protected Access - Pre-Shared Key) - and that key is transmitted with encryption. Older networks used WEP (Wired Equivalent Privacy) which was flawed and just a little better than no security at all - which is what most of these vintage devices can/will use (but more on that later).
(WiFi to Ethernet Bridge)
A Wireless Bridge is a device that allows Ethernet Connected devices to use the WiFi network for connectivity. These devices are configured over Ethernet using a set, default IP Address, and then attached to the device that is using them so the device can behave as usual, while it's network traffic is sent and recieved and passed along by the Wireless Bridge Device. These can be VERY useful in households that want to connect vintage Desktops to a Wireless home LAN, which is becoming the preferred way to have devices connected in the home anyway.
(Power Line Communication Devices)
These devices attach to your Power Line, and send network signals over the wiring inside your house. Basically, the device plugs into a wall outlet, and connects to the device via Ethernet. However, these devices need to be on the same circuit inside your home for optimal transfer rates and communications speeds, sometimes even to commuincate at all.
(Network Interface Card)
This is the piece of your vintage computer that talks with the actual network. Most of these we'll be dealing with here will be Category 5 Ethernet based TP (Twisted Pair) Ethernet adapters made in the 1990's and later, capable of 10 megabits per second over a good connection. Most of these plug into ISA/EISA/PCI slots in your computer, and the maximum throughput speed is determined by the system bus. ISA tops out at 10mbps, while PCI tops out around 100mbps (10/100). Modern PCI-E machines are capable of a Gigabit per second or better. Lucky us, the files and data are so small going to these old machines that 10mbps seems nearly the same as 100 or 1Gbps on a modern machine.
(Wireless Card)
Basically a "Wireless NIC", WiFi Cards started off primarily as either PCMCIA (Personal Computer Memory Card Association) and Cardbus cards running on the 802.11b standard (11mbps) on laptop computers, or as the same cards installed in a PCMCIA Adapter device that allowed them to be plugged into ISA or PCI slots on a regular desktop when Ethernet was not available. Most of these early WiFi cards used WEP encryption - aka "Wired Equivalent Privacy" - which is now a big No No due to security concerns in the present time, even though it's still available to use in a lot of cases. AS such, it can be a bit of a hassle to use such cards. One way I found is to use a cellular phone Tethering that allows only ONE device and only enable it when its in use. There's another way around this problem by using a "Serial WiFi Modem" device like those sold by TheOldNet.
(aka. Cat5e or Cat6e)
The cabling we use for connecting all the wired equipment up with. While most old Network Interface Cards might have BNC or AUI Ports on them, the majority you can find should have Ethernet Twisted-Pair connections on them that you can use without some kind of adapter.

Now that we have established what these devices are, let's talk about your "signal chain" if you will, for lack of a more layman set of terms.

The most typical setup you will encounter using discreet components is Gateway->Router->Switch->and then that fans off into the wireless access point the wireless clients connect to, and then all your ethernet "clients" on the network.

The Gateway would be your access point to the internet your ISP fees you every month for, usually made by Cisco, or Arris, or some other brand you've never heard of before. This should be of little to no concern to you. Often these come with a switch and Wireless Access point built into it these days.

The router often has a switch and Wireless AP built into it these days. But let's assume you're using old networking equipment, then your router would be placed just before the Gateway. What the router does, is what it says - routes traffic to and from the internet, and to and from other parts of the network.

The Wireless Access Point is often integrated into the Router unless you're using enterprise class equipment. This usually broadcasts an SSID - or Service-Set-IDentifier, IE, all the funny little names you see for your neighbor's wireless networks surrounding your house/apartment unit like "IRS Surveillance Van 110" or "Mormons in Space" or "Put Ur SSN Here". Connecting a vintage computer, especially of the 486 or older pursuasion, to one of these types of networks requires some special hardware to do it with proper security. Old networks were unsecured in the days before everyone knew how to basically "use" a computer, then came "WEP" encryption, or Wired Equivalent Privacy, which did almost f***-all to protect your wireless network. Last is WPA2-PSK or WPA-PSK, which are the modern versions of such that most people use. These stand for Wireless Protected Access - and the "PSK" at the end stands for "Pre-Shared Key" - ie a PASSWORD you create to protect it from unauthorized access, by not providing it to people you don't want to give access to your network to. But more on that later. There IS a way to connect a vintage client to these networks, and it's really not that hard either.

Lastly are your "Ethernet Clients" which most of us will be using for these types of devices. These are "Wired network" or "ethernet" connected clients that connect to the switch. Originally, I used "Hubs" to do this. The difference between a Hub and a Switch is a Switch has actual "logic" in it to allow it some routing capabilities. There are two types of switch, the regular, unmanaged type most of us will have at home, and then the "managed Switch" type we'll find in a corporate office. Managed Switches give us more abilities to manage traffic, such as splitting ports off into VLANs or "Virtual LANs" for further protection and to allow for better allocation of IP Addresses within a certain range to certain equipment for both management and security reasons. You also can use ACL's on a manged switch - Access Control Lists - to control access to certain things as well. But that's out of the scope for this document. I highly doubt most of us reading this would be messing with some kind of Cisco Catalyst enterprise-level switch, LOL.

The computers themselves will need either one of the following to be network capable - either a NIC or "Network Interface Card" which is an ISA or PCI (or even EISA) card with an ethernet port on it that allows for connectivity to a network. There are other connection types but I suggest against using them because it's going to make your life using a vintage computer a huge pain in the ass. You will need a Cat5e cable for it, but Cat6 or higher should also work if that's all you have.

But what if you want to connect these machines in a room on their own, or even in a garage, and don't want to drape 9-miles of ethernet across your house? Well, then there's the possibility of usinga Wireless Bridge. While the afore-linked page mentions my experiments with this, I'm also listing it here for a "one page suits all" sorta' deal.

Basically, instead, you plug the Wireless bridge into the ethernet port on a laptop computer, put in a default IP Address provided by the manufacturer, and default login credentials, and then usually run a wizard or manually configure it to connect to your WPA/WPA-2 wireless network. Then that device will act as a liason between the vintage PC and the modern Wireless Network. It also SEEMS to add some security by obscurification of the computer's identity to the network and/or the internet without directly addressing it.

And with all that squared away, you now have your computer connected to the network physically. I will be adding more guides to different bits in detail on connecting specific operating systems in their related sections on the site. I also am going to provide a VINTAGE NETWORK page here for general vintage network stuff outside of the O/S - basic stuff you need to know to properly configure a TCP/IP network, and do so SAFELY with these machines.