All the jargon is quite confusing...
Absolutely, but with all the help from yourself and others I think I've boiled it down without the jargon in simple language a G8(retired) and non Nerds can understand:
BT/Openreach own the copper wire from your house. They go to the first street cabinet. Inside the street cabinet there's a bridge from copper wires to fibre and a link from copper wires to their wired (PSTN) phone line network. In my area the copper wires pass through many street boxes and underground ducts to reach the exchange several miles away.
This convoluted network of copper wires and connections from the first street cabinet can be unreliable and engineers spend a lot of time and money repairing faults, whereas the shorter copper wires from house to the first street box generally is reliable because there may be only 1 or to junctions.
If the distance between your house and the exchange is very short you can have a broadband service over wires whose speed is set by the length of the wires, but optimistically won't be more than 30Mb/s? If your first street cabinet is close to your house and has their fibre run to it like mine, you can have faster speed broadband over fibre BUT LIMITED BY THE SHORTER LENGTH OF COPPER between your house and the cabinet. In my case I can get up to 80mb/s broadband reliably, but my phones on copper wires to the exchange are always going faulty or crackle with poor sound.
If you are lucky and have a fibre cable specifically allocated to your house and nobody else owned by BT, Virgin or another, your house can be connected by fibre all the way into the Super Fast network (Owned by Openreach). You cannot connect to these unless you have contracts with the fibre owner or a third party has arrangements in place to pay and bundle in the cost of maintaining them. At the moment Plusnet and others pay BT/Openreach for renting the complete copper line PSTN system to the exchange as a landline charge for a landline phone and broadband. Depending on your post code, broadband can use a shorter wire hop house to fibre, a longer hop to fibre, or all the way to the exchange on wires. Using postcode searches to get speeds gives clues as to what type of route your broadband is taking. If you have a broadband only contract with no phone, why should you pay the full landline rental charge to use the first hop of copper wire?
BT/Openreach have decided to abandon the wired network from the first cabinet on long unreliable routes to their exchange, but keep wires from your house to the first cabinet. If you want a 'Landline phone' they will convert the phone signals to digital voice and your phone service will appear to work the same but is actually VOIP. That's fine if you have BT contracts because they own the first stage of the line and kit. In future we may see Openreach replacing the first wire hop between cabinet and home with fibre to give you full fibre to the home (FFTH), but who pays and how much? In many areas cabinet to home wires are overhead on poles but I'm not sure if fibre can take the same overhead route, or has to be in expensive new underground ducts?
The SoGEA option was created to allow 3rd party broadband providers access to the first wire hop home to cabinet then use the Openreach fibre network. A line rental charge is still there or hidden in the bundle, but should be lower for the short run and there's no access for a landline phone.
The problem looming for all of us wanting to keep our landline number and not abandon it to use mobile phones is VOIP cannot be avoided unless you are a radio amateur or use mobile phones exclusively. Only BT at the moment seem to be offering an end to end substitute of the old kit and connection bundled into their broadband contracts, whereas many would rather choose independent providers for their broadband and voice, or use mobile phones and not have voice at all.
