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Posted

Why IP telephony haven't become a landline communication standard yet? Some people say this is because Internet is less reliable than phone. But why is it less reliable if exactly the same hardware is used for signal transmission? If hardware is different, where exactly the difference is?

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Posted

The same hardware is not used for signal transmission. "Phone" includes cellular technology. My guess is that VOIP has taken a back seat to cell phones, and may be considered a niche market at this point.

Posted
4 hours ago, Sensei said:

http://www.anorak.co.uk/383464/money/skype-is-now-40-of-the-entire-international-telephone-market.html/

"Skype Is Now 40% Of The Entire International Telephone Market" (as of 2014 year)

Misleading headline. "Skype’s traffic was almost 40% the size of the entire conventional international telecom market" which means it's 28% of the international market, assuming there are no other participants. Not sure if "conventional" excludes cell or not.

How big is the international market vs the domestic market?

Posted
8 hours ago, swansont said:

The same hardware is not used for signal transmission. "Phone" includes cellular technology. My guess is that VOIP has taken a back seat to cell phones, and may be considered a niche market at this point.

I can't understand that. Don't signals go the same physical routes if you use VOIP, Skype or PTSN?

Posted

I think the key is packet delivery in "real time".  UDP or TCP IP packets can be delayed finding routes through the internet and delayed by heavy traffic connections or even from local interference of wifi signals.  Plus some service providers were caught intentionally delaying packets used for voice presumably to sell their expensive phone communication.  Why would anyone use an expensive phone plan when Video/Audio chat is better and data rates are cheaper?

 

Posted

Phone and TV over cable are provided by Virtual Private Networks which are allocated to reliably deliver the service, where regular internet protocols are vulnerable to user traffic.

Posted
8 hours ago, Frank said:

I think the key is packet delivery in "real time".  UDP or TCP IP packets can be delayed finding routes through the internet and delayed by heavy traffic connections or even from local interference of wifi signals.  

 

Why fiber optic cables still didn't replace copper cables completely? Is it so much expensive? I thought that once installed optic cable can serve for many decades? 

Posted
9 hours ago, Moreno said:

I can't understand that. Don't signals go the same physical routes if you use VOIP, Skype or PTSN?

Do they go the same way if you use a cell phone?

Posted
25 minutes ago, Moreno said:

Why fiber optic cables still didn't replace copper cables completely?

This is partly cost and partly just a matter of scale. It is already available to most cities. And I have seen engineers installing fibre-optic cables in the towns around where I live. I have no idea when they might go live. And how many more years before it reaches all the smaller towns and villages in between.

Posted
3 minutes ago, Strange said:

This is partly cost and partly just a matter of scale. It is already available to most cities. And I have seen engineers installing fibre-optic cables in the towns around where I live. I have no idea when they might go live. And how many more years before it reaches all the smaller towns and villages in between.

And the question is focusing on a small fraction of the population of the world. Some places are not installing this infrastructure (the cost component — its very expensive to do that). There was no copper to replace with fiber, and fiber is not being installed.

Posted
8 minutes ago, swansont said:

And the question is focusing on a small fraction of the population of the world. Some places are not installing this infrastructure (the cost component — its very expensive to do that). There was no copper to replace with fiber, and fiber is not being installed.

True. I have read that many parts of the world, Africa for example, have gone directly to wireless communications and mobile phones completely bypassing copper and probably fibre. (One challenge for copper in many places has been that as soon as it is installed, it is stolen!)

Posted (edited)
2 hours ago, swansont said:

Do they go the same way if you use a cell phone?

The same strange story is with mobile phones. If you have mobile Internet you can make calls for free using Whattsap to any location in the World. But you cannot make calls using Whattsap to a landline. I guess it would be much easier if every stationary phone would support VOIP? I hope that fiber optic cables will provide more than enough capacity for everyone not to have excuses about traffic congestion anymore?

Edited by Moreno
Posted
52 minutes ago, Moreno said:

The same strange story is with mobile phones. If you have mobile Internet you can make calls for free using Whattsap to any location in the World. But you cannot make calls using Whattsap to a landline. I guess it would be much easier if every stationary phone would support VOIP? I hope that fiber optic cables will provide more than enough capacity for everyone not to have excuses about traffic congestion anymore?

But if neither person has a landline, what would be the point?  In the US, half of the country has no landline anymore.

Posted
3 minutes ago, swansont said:

But if neither person has a landline, what would be the point?  In the US, half of the country has no landline anymore.

So, you propose to give up cables and switch to wireless completely? Not that I would be against of it but for now people don't seem ready to do that. Wireless is more susceptible to interference, what may create danger in case of emergency. It always good to have a reliable back up in the form of landline. But maybe it will ultimately come to this. What do you think about distributed wireless networks? It's when cell towers are replaced by smaller antennas located in the households and when these antennas create cooperative peer to peer network. Do you think it can reduce energy consumption and increase reliability? Also, I have question about UWB technology. Why does it have short range if it doesn't cause interference with anything? https://en.wikipedia.org/wiki/Ultra-wideband

Posted
2 hours ago, swansont said:

And the question is focusing on a small fraction of the population of the world. Some places are not installing this infrastructure (the cost component — its very expensive to do that). There was no copper to replace with fiber, and fiber is not being installed.

There are currently several plans from solar airplanes to LEO satellites to make an internet for all. Full wave antennas will be shorter than 1.2 cm, which suggests that mobile internet access is possible to a swarm of LEO satellites. If this technology is developed, anyone could walk around with a VOIP telephone.

Posted
29 minutes ago, EdEarl said:

There are currently several plans from solar airplanes to LEO satellites to make an internet for all. Full wave antennas will be shorter than 1.2 cm, which suggests that mobile internet access is possible to a swarm of LEO satellites. If this technology is developed, anyone could walk around with a VOIP telephone.

Not quite, until it will be accepted as a standard by everyone. I'm not sure that the final obliviation of the landline will pass completely painlessly. Fiber optic still provides much higher capacity than wireless. Govt. organizations don't hurry switch to wireless. Etc.

Posted
18 minutes ago, Moreno said:

Not quite, until it will be accepted as a standard by everyone. I'm not sure that the final obliviation of the landline will pass completely painlessly. Fiber optic still provides much higher capacity than wireless. Govt. organizations don't hurry switch to wireless. Etc.

When high speed is required, e.g., GHz sustained for long periods, fiber optic is great; I expect a mixture of fiber and wireless. Point to point landlines will eventually go away. Wireless communication technologies have similar restrictions, but satellites may have less bandwidth than a cell network. Maybe the balance is to use cell towers for hi density population centers and satellites for rural.

There is a hole in the atmosphere for EMR at 300 THz. If it can be used, perhaps satellites will have much more bandwidth.

Posted
1 hour ago, EdEarl said:

There are currently several plans from solar airplanes to LEO satellites to make an internet for all. Full wave antennas will be shorter than 1.2 cm, which suggests that mobile internet access is possible to a swarm of LEO satellites. If this technology is developed, anyone could walk around with a VOIP telephone.

If you already have internet on your phone through your phone provider, what would be the point?

I don't make international calls, so I am not a potential customer for such a service. The notion of long-distance evaporates once you go with a cell phone. I imagine that I am not alone in this regard (I suspect I'm in the majority) 

Posted
5 minutes ago, EdEarl said:

There is a hole in the atmosphere for EMR at 300 THz. If it can be used, perhaps satellites will have much more bandwidth.

Interesting. Can you give some link about it? Does it suppose to work like a laser then?

2 minutes ago, swansont said:

If you already have internet on your phone through your phone provider, what would be the point?

Probably, he hopes for a "free lunch".

Posted
1 minute ago, swansont said:

If you already have internet on your phone through your phone provider, what would be the point?

True, cell also provides internet. The point, there are two ways to achieve the same thing. Perhaps both have a niche, perhaps not. Time will tell.

4 minutes ago, Moreno said:

Interesting. Can you give some link about it? Does it suppose to work like a laser then?

Info about the hole is in Wikipedia. AFAIK 300 THz has no commercial application, and the technology is not yet being developed. However, as electronics switches improve their speed, higher frequencies have become possible to use for communications. IDK where the limit will be.

Posted
3 hours ago, Strange said:

True. I have read that many parts of the world, Africa for example, have gone directly to wireless communications and mobile phones completely bypassing copper and probably fibre. (One challenge for copper in many places has been that as soon as it is installed, it is stolen!)

I thought that a mobile phone connected to a tower, which then routed the call over copper and/or fiber, and ultimately to the recipient. Is that not necessarily the case? Might calls simply travel from tower to tower wirelessly from caller to receiver?

Posted
53 minutes ago, EdEarl said:

Info about the hole is in Wikipedia. AFAIK 300 THz has no commercial application, and the technology is not yet being developed. However, as electronics switches improve their speed, higher frequencies have become possible to use for communications. IDK where the limit will be.

At that frequency it is going to be a thing ray of IR radiation. At which exactly points on Earth a satellite suppose to send it?

Posted (edited)
14 hours ago, Frank said:

I think the key is packet delivery in "real time". 

The key is whether signal is digital or analog, the key is whether signal is compressed or uncompressed.

Analog data are not compressed = single cable can transmit very small quantity of simultaneous voice transmissions.

Digital data can be compressed: lossless compression (e.g. PNG, GIF, WAV) or lossy compression (e.g. MPG, MP3, DivX)

Same cable transmitting compressed digital data, can contain dozen more data than the same cable transmitting analog signal.

 

14 hours ago, Frank said:

UDP or TCP IP packets can be delayed finding routes through the internet and delayed by heavy traffic connections or even from local interference of wifi signals. 

UDP packets don't demand confirmation of delivery from recipient. So sender (application) does not know whether data arrived to recipient at all.

TCP packets require confirmation from recipient. If packet is lost, there is demanded resending of data. It slows down transmission a bit.

 

VOIP usually uses UDP. Human can hear if there is a transmission error, the loss of some packets, as a crackling sound. And then you can tell other human to repeat.

 

Edited by Sensei
Posted
13 minutes ago, Moreno said:

At that frequency it is going to be a thing ray of IR radiation. At which exactly points on Earth a satellite suppose to send it?

I haven't done any calculations, it's some time off before that technology is available. A phased array antenna can be steered electronically. Maybe it can be done without the antennas pointing at each other; although, that typically requires higher power, so fixed antennas may be eliminated. Technology must be able to do the 300 THz communications from antenna to human interface, but there is no guarantee it can be done at this moment. 

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