The Sinclair QL Forum

Hi
Back in the day (1980’s) modems speed were in kilobites and Ethernets were 10Mbps (bits per second). By the early nineties fast Ethernet (100Mbps) was being introduced for our CAD/CAM Desks and we had a campus backbone over Fiber of 150Mbps. By the end of the nineties, we were already rolling out Giga bit per second (1000Mbps) to connected devices.

Jump to present day
The UK as with many other countries is committed to rolling out Fiber Broadband to replace the present ISDN and PSTN Telecoms networks. For Phone connections ie. Landlines the Service is being replaced with Voice over Internet Provider (VoIP).

Being in a small village FIBER was first promised for 2018. Well Jan 2025 I’m now finally connected.

Yes, the download and upload speeds are much faster although the opening phase of setting a new connection is sometimes slower than before. I guess with all the Network changes going on this might be expected. Our newest Laptop has Wi-Fi 6 with average speed checks of 135Mbps Download and 120Mbps Upload. My old and trusted Desktop was at times having connection problems and only 4.5/1.2 Mbps Load speeds. I considered maybe this was the time to replace it. But a little research and for less than £15 I found a Wi-Fi 6 USB3 Adpter. Download and Upload speed are now in the range of 30Mbps plus.

All said and done my Phone changeover from ISDN to VoIP took a week. The problem was escalated and it seems others have had similar delays. My IT and Telecoms background kicked in and from memory I recalled that when you physically disconnect an ISND wired connection the call doesn’t go Number Unobtainable but Busy. This is what calling our old landline number was doing. So, on my last call to get our Phone fixed I suggested that perhaps Openreach hadn’t switched off/deleted our old ISDN routed connection. Strangely within twenty minutes our phone line was up and working.

I was also told my home extension wiring would not work and was supplied with an adapter that uses a Wi-Fi connection to the supplied Router. The first one sent out sort of worked but then decided to do weird things. Another was sent as a replacement. Connecting our main Phone directly into the Router Phone jack and using the extension with the adapter it appears you can pick up from either but cannot join the conversation with the other phone as we used to do over our existing wiring. Well, some checking and it appears you can connect the Router Phone jack to the extension wiring using a Male-to-Male Phone cable. I wired a twin Phone Jack as a splitter replacing the one Openreach had decided to remove and connected it with the house extensions. Now the Phones work as before. The attached sketch is my take on our Fibre connection and internal Phone setup with VoIP.

Ho! The Joys of new Technology and its ever increasing ability to confuse and bewilder..

QBITS

That's a lot of work to avoid having a mobile

Interesting that there's still ISDN in the UK. I had ISDN until 2010, when I migrated to fiber (having had DSL for my internet connection since 2002 and cable internet since 1998).
In Holland, ISDN has been discontinued since a few years, and POTS is also rapidly being dismantled.
(My town was quite early to get fiber in 2010; it's still being rolled out in other places).

As far as I can remember, a disconnected ISDN line resulted here in a 'Number unobtainable' signal, at least when the loop between exchange and NT was open.
One disadvantage of VoIP: it's impossible to get a connection between POTS modems over it, unlike ISDN!

I thought it was possible to get modems to talk over VoIP - as long as some tuning was done? (generally tuning downwards - for both speed and some of the features that allow the maximistion of the 4 quadrants - so you may be stuck with 14K4 - or a max of 33K but in theory it should still be possible.

Some further info here:

https://area-51.blog/2021/01/16/getting ... with-voip/

Pr0f wrote: Wed Jan 29, 2025 10:12 pm I thought it was possible to get modems to talk over VoIP - as long as some tuning was done? (generally tuning downwards - for both speed and some of the features that allow the maximistion of the 4 quadrants - so you may be stuck with 14K4 - or a max of 33K but in theory it should still be possible.

Whether an old legacy modem works on VOIP lines or not depends on the codec(s) your provider has configured and offers for negotiation to your devices. Most European telcos use a-law, US mostly uses µ-law. The latter works acceptably with legacy modems, the former doesn't (or, only with very, very low connect rates). Some European providers use multiple codecs and allow the end user/device to select during the negotiation phase. There are more standard codecs (G-722, G-726, G-729)with varying frequency bandwidth and digital bandwidth usage that will also affect modem connectivity. So, overall, it depends on your provider.