USP will advise, but we are not in the connectivity supply business. Google and your postcode are your friends when looking for a supplier.
ADSL/Broadband is an "always on" service - your data rate depends on your location, but with the expanding deployment of you could get anything up to 1000MBit (FTTP), although 30-40MBit is more usual (FTTC). ADSL still mostly uses an existing copper phone line from the street cabinet to your premises, and can be user-fitted - or installed by an engineer.
You probably already have a DSL connection, and the odds are you get it from one of the big providers with call centres from hell, and a service that feels like it is shared with a million users who all seem to want to watch EastEnders on iPlayer, and take all the available bandwidth. You might also be tied into a 24 month contract if you did not read the small print.
Although many service providers use BT fibre and copper lines to deliver their services, they actually manage the "other end" of the connection quite differently to BT, and so can offer benefits that BT and most other big services do not.
If you need a bespoke service then USP will advise on specialist solutions providers; we do not generally get involved in supply contracts.
Most ADSL routers now include rudimentary Wi-Fi facilities, but in reality, this only works over 30-40 feet in most building environments. You may need Wi-Fi repeaters to cover the complete area; and you may need a specialist installer. As wifi has become ubiquitous, the congestion of the radio spectrum means that there may be as many as 30 Wifi access points visible on your device.
Dial-up connectivity means modem connections across traditional (analogue) telephone connections - also known as "POTS" (plain old telephone service) - and this means call charges per minute. It is still the only means of access in some parts of the world, but can largely be discounted as a viable option in most countries. With copper POTS telephone line services being decommissioned by 2025, it's all over for dial-up.