5 ms·

> I love landline phones (when they work right, which is not the case everythere) because usually they have better sound quality than mobile (which can be good-

> I love landline phones (when they work right, which is not the case everythere) because usually they have better sound quality than mobile (which can be good-to-horrible depending on network quality) and almost zero latency. That was the old landlines, of actual POTS, era. Back then, there was a direct electrical circuit literally switched using relays between both participants in a call, with only amplifiers, switches and power sources in between. More modern systems used banks of relays, and then it all went downhill quality-wise. First, the telco core systems were replaced with digital trunks that had ADCs on both ends of a call in the regional distribution center, and consumers were switched over to ISDN for telephony. Then, the analog/ISDN frontends moved to the curb side where ADSL, VDSL and nowadays G.fast frontends were added to the mix, which were connected to the telco network using fiber. Then, analog and ISDN were shut down, with voice phone calls being migrated to VoIP. And nowadays, it's the full evolution with GPON - on the telco side, there's only fibers and a single TX/RX pair of transmission modules serving up to 64 customers. What used to require a whole multi-story building can now be done in the space of a better-quality shed. And the analog frontend is only at the CPE, if there is an analog frontend present at all and it's not VoIP softphones or DECT.

Dibby053 2y ago
My new ISP took this to another level: if you transfer your landline phone number they send you a voice-only SIM card and a 4G router into which you're supposed to plug your landline. Calls to the landline number are redirected to the number in the SIM (with a significant delay). I wonder why they did it this way instead of implementing VoIP, especially since the all-in-one GPON/Wi-Fi router already has a landline port.
- actionfromafar 2y ago
  Maybe requirements on availability?
- dfc 2y ago
  What ISP do you use?
- ale42 2y ago
  This sounds terrible :-O
toast0 2y ago
In the US, at least in the states I lived in, ISDN telephony was always niche, the price was too high unless you needed it for a remote studio, or you had a teleconference setup or needed the blazing fast 128kbit dial up experience. Analog phones with a digitizer at the central office or remote terminal is still a very good calling experience with minimal latency. 8-bit u-law @ 8000 Hz isn't great audio quality, but the sampling delay is near zero, and when it was all PRI digital (t1/isdn/etc) switching, multiplexing was done per sample, so there was no significant buffering (a two sample buffer would be sufficient at any switching point). Mobile uses complex compression with significant sampling delay and sends data in bursts so there's packetization delay. VoIP often uses complex compression (but you can configure for u-law) and is usually 20ms packets, plus you've got to add a jitter buffer to account for packets taking different amounts of time to traverse the network. Packet switching clearly won over circuit switching, but we've lost the very low latency local calling we used to have, and I don't think anyone is willing to send 1000 packets per second for voice calls to get close to where we were. For long distance calling, probably improved routes that were run for packet switching reduce latency enough to cancel out the increased factors.
freeopinion 2y ago
I'm not sure what you mean by "better-quality shed" but cabinet sizes today are often less than 1 cubic meter. I guess you know that, but thought it might surprise some people. One cabinet doesn't really replace a multi-story building. Many cabinets spread out over the service area do the job. But each cabinet can perform all the functions that used to happen in the large building. They just make it economical to perform those functions for 100 - 1000 subscribers, instead of having to centralize them into a single location that serves 5,000 - 100,000. Those cabinets are not a result of fiber. They were more a necessity of high bandwidth services without fiber. Think ADSL. Fiber actually makes it possible to go back to more centralized service while providing even more bandwidth. You can deploy passive fiber splitters in an old-fashioned pedestal and keep the active optics in the multi-story building for 100,000 subscribers again. Maybe you meant that the active optics would only fill a small shed's worth of space in that old building. I finally caught up to you.
- fleventynine 2y ago
  With 64 XGS-PON customers per SFP+ module, the only active equipment you need to terminate connections for over 60,000 customers fits into a single rack. Large centralized buildings are largely obsolete unless you want to offer services beyond basic Internet access.
  - freeopinion 2y ago
    Yep. And services like voice for 60,000 only takes 1/4 rack.
- mschuster91 2y ago
  The large space savings IMHO come from getting rid of the point to point connections via these massive 2000+ wire cables and their corresponding patch panels and routing infrastructure. With GPON you only need a single SFP module and passive optical splitters in the underground buried junctions, no need for any roadside equipment. (Worked as a trench digger / roadside equipment box installer once in younger times)

Dibby053 2y ago

My new ISP took this to another level: if you transfer your landline phone number they send you a voice-only SIM card and a 4G router into which you're supposed to plug your landline. Calls to the landline number are redirected to the number in the SIM (with a significant delay). I wonder why they did it this way instead of implementing VoIP, especially since the all-in-one GPON/Wi-Fi router already has a landline port.

actionfromafar 2y ago
Maybe requirements on availability?
dfc 2y ago
What ISP do you use?
ale42 2y ago
This sounds terrible :-O

toast0 2y ago

In the US, at least in the states I lived in, ISDN telephony was always niche, the price was too high unless you needed it for a remote studio, or you had a teleconference setup or needed the blazing fast 128kbit dial up experience. Analog phones with a digitizer at the central office or remote terminal is still a very good calling experience with minimal latency. 8-bit u-law @ 8000 Hz isn't great audio quality, but the sampling delay is near zero, and when it was all PRI digital (t1/isdn/etc) switching, multiplexing was done per sample, so there was no significant buffering (a two sample buffer would be sufficient at any switching point). Mobile uses complex compression with significant sampling delay and sends data in bursts so there's packetization delay. VoIP often uses complex compression (but you can configure for u-law) and is usually 20ms packets, plus you've got to add a jitter buffer to account for packets taking different amounts of time to traverse the network. Packet switching clearly won over circuit switching, but we've lost the very low latency local calling we used to have, and I don't think anyone is willing to send 1000 packets per second for voice calls to get close to where we were. For long distance calling, probably improved routes that were run for packet switching reduce latency enough to cancel out the increased factors.

freeopinion 2y ago

I'm not sure what you mean by "better-quality shed" but cabinet sizes today are often less than 1 cubic meter. I guess you know that, but thought it might surprise some people. One cabinet doesn't really replace a multi-story building. Many cabinets spread out over the service area do the job. But each cabinet can perform all the functions that used to happen in the large building. They just make it economical to perform those functions for 100 - 1000 subscribers, instead of having to centralize them into a single location that serves 5,000 - 100,000. Those cabinets are not a result of fiber. They were more a necessity of high bandwidth services without fiber. Think ADSL. Fiber actually makes it possible to go back to more centralized service while providing even more bandwidth. You can deploy passive fiber splitters in an old-fashioned pedestal and keep the active optics in the multi-story building for 100,000 subscribers again. Maybe you meant that the active optics would only fill a small shed's worth of space in that old building. I finally caught up to you.

fleventynine 2y ago
With 64 XGS-PON customers per SFP+ module, the only active equipment you need to terminate connections for over 60,000 customers fits into a single rack. Large centralized buildings are largely obsolete unless you want to offer services beyond basic Internet access.
- freeopinion 2y ago
  Yep. And services like voice for 60,000 only takes 1/4 rack.
mschuster91 2y ago
The large space savings IMHO come from getting rid of the point to point connections via these massive 2000+ wire cables and their corresponding patch panels and routing infrastructure. With GPON you only need a single SFP module and passive optical splitters in the underground buried junctions, no need for any roadside equipment. (Worked as a trench digger / roadside equipment box installer once in younger times)