Eric The Viking
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Just to add further clarification:
Terminology:
Hope that's handy for someone.
OK, bored now. Will have to go paint the house <sigh>.
Terminology:
- POTS = "plain old telephone system"
- Local End (GPO/BT) = Local Loop (USA - now pretty global usage) = the pair of wires between your house and the exchange in a POTS system. Often also (mis-)used for the broadband connection between house and nearest aggregation point (usually a green box on the pavement, or a box down a manhole).
Local ends are ubiquitous, and almost always BT/Openreach provided and maintained. The nearest point to your house where your ISP's hardware can be is the local Openreach telephone exchange, where they may[/iu] have a rack of equipment, but often they just use what BT/Openreach provide, and performance differences, if any, happen much further upstream. The exception is Virgin, who have their own infrastructure in the pavement in many places, the City of London (the square mile), where Hutchison and others provide circuits. And Kingston on Hull, which is slowly drifting into the north Sea by itself.
[*]ADSL = asymmetric digital subscriber line. It's asymmetric because it's faster coming to you than going out. Commercial premises can have SDSL ("Symmetric..."), at a significant extra price. This technology uses old-fashioned phone lines and is limited by the quality of the local end (length, condition, route taken, etc.).
[*]Fibre = in this context, usually an optical link to the exchange or green box. Pretty dashed quick, but comes with a whole new set of awkwardnesses, for example you can't bend it through tight radii, and putting plugs on the ends can involve equipment costing thousands. Also it's useful to be lucky (from a customer perspective), as a whole new set of engineers are being hurriedly "trained" in the technology - presently many of them actually know what they're doing.
Proper fibre will work over relatively long distances and the "wire" is cheap (oddly it's always written "fibre", not "fiber", even in the USA), so it's a good way of getting fast connections into rural areas, although presently the equipment at both ends is still pricey compared to older technologies.
[*]Modem = "Modulator/Demodulator". This used to be something that converted digital signals to pings, whoops and whistles down a POTS line, by a process of witchcraft. Now, boringly, it usually means the box between your kit and the connection leaving the premises. It still does do a conversion, but no pings or whistles are usually involved any more (shame!). The function of a modem is often combined with that of a router and a firewall and WiFi access point, in one plastic box, so you can buy things called ADSL modems, which are rarely only that.
[*]Router = "rooter" (not "r-ow!-ter" for dadoes and the like). This isn't a physical object, but a small computer system (OK, they do often come in self-contained plastic boxes!). It could best be thought of as a postal sorting office. It knows how to send-on addressed packets (of data), either to a something on your home network, or from your network onwards into the greater internet. To do this it follows rules, most of which are automatically learned or pre-programmed, but some of which you can add and change (gamers do this, to tune routers for faster connections for the games they play).
As is, routers offer almost no security. That comes from:
[*]Firewall = a system (i.e. programs that run), intended to break (like a fuse) if attacked, instead of your important computers being broken. That was the original meaning (20+ years ago) - think firebreak in forestry - and it was a physical, separate machine between a home network and the internet, so if it was crashed, nothing nasty could get further. Nowadays it just means a system to block attacks from the internet.
Firewalls run on ADSL routers/modems, and even on mobile 'phones. You can hardly ever tell if they're any good or value for money, incidentally. To do what they do, Firewalls also use witchcraft, mostly involving the sacrifice of goats and, oddly, small yellow lizards.
Wise old IT professionals not only carry a staff and wear a pointy hat (with "Wizzard" on it), but they never trust firewalls to do what they claim, without constant updating and tuning. You have been warned.
Hope that's handy for someone.
OK, bored now. Will have to go paint the house <sigh>.
