1. What is the purpose of this document?
This document attempts to cover FAQs concerning using the Internet for placing long distance calls. At present, the main thrust of the document is to deal with services that offer telephone-to-telephone service, that is, where a plain old telephone is used for both the caller and the callee.
There are other forms of VoIP such as PC-to-PC communications (See What is PC-to-PC VoIP communication?) or "Hardware Phones" (See What is a hardware phone?) that will only be mentioned in passing here.
2. What does "Internet Telephone" or "Voice Over IP (VoIP)" mean?
VoIP means "Voice Over Internet Protocol", in other words, using the Internet to carry the conversation between the participants.
The are currently two largely separate universes of connections between any two points on earth – the telephone companies' systems and the Internet. In some cases, the same physical connections are used and in some cases, they are not.
Pricing for Internet access is not currently based on the amount of data sent and received, whereas the traditional phone companies usually charge by the minute. As a result, VoIP becomes attractive in that it can offer unlimited long distance access.
For a more technical explanation of VoIP, see Can you explain VoIP in a bit more detail?.
3. What companies are offering VoIP in Israel?
Several companies offer VoIP. The main two Packet8 and Vonage are in the United Staes. Neither supports users outside of the U.S.
VoIP has yet to take off in the UK or Europe, but Oftel (the UK agency that regulates telephones) has said they are very supportive of VoIP and will be working with Service Providers to make it available soon.
Amerifone resells Vonage service in Israel. They provide installation and customer service for a price.
| Amerifone | +1 800 555-5555 |
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| Delta3 | +1 800 555-5555 |
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| Free World Dialup | +1 800 555-5555 |
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| MSM NetPhone | +1 800 555-5555 |
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| Netvision | +1 800 555-5555 |
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| Packet8 | +1 800 555-5555 |
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| Vonage | +1 800 555-5555 |
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| Company | Int? | Initial | Month | Other | Obl | Loc |
|---|---|---|---|---|---|---|
| Packet8 | yes | 8888 NIS | $39.95 | 10% | 24 | Zanzibar |
| Vonage | yes | 8080 NIS | $49.95 | 15% | 36 | Bulgaria |
Legend:
| Int? | Integrated? That is, do the customer use a regular telphone plugged into a router as opposed to a headset and microphone plugged into a computer? |
| Obl | Obligation, that is, the number of months for which a customer has to sign up. |
| Month | Monthly charge |
| Other | Other hidden charges such as taxes or surcharges |
| Loc | Location, that is, the country of the customer's telephone number. |
7. How does the customer dial out?
To be answered
8. What sort of high-speed internet access is reqired?
To be answered
9. What equipment is installed?
Amerifone sells you a Mototorla or Cisco devices that connects your regular telephone and your computer network.
To be answered
11. How do features such as call-waiting, last number redial and follow-me work?
To be answered
12. How do special numbers such as police, MDA, and fire work?
To be answered
13. What other advantages and disadvantages are there to this service?
To be answered
14. How can I get Vonage service in Israel?
Amerifone resells Vonage service in Israel. They provide installation and customer service for a price.
The current set of volunteers consists of:
| ahuva12 | ahuva12@yahoo.com | Canadian phones |
| Gary Wardell | gwardell@ApprovalSystems.net | user from the US |
| Geoffrey S. Mendelson | gsm@mendelson.com | general knowledge |
| Ira Hauser | limjts@NETVISION.NET.IL | sent answers |
| Jeff Finger | jfinger@cs.stanford.edu | Coordinator |
| Moshe Maeir | m345@netvision.net.il | represents MSM Netphone |
| Nayman Zvi | znayman@yahoo.com | sent answers |
| Yocheved Krems | krems@actcom.co.il | technical writer |
| Yonah Sudwerts | yonah@bezeqint.net | sent answers |
| Zachary Kessin | zkessin@cs.brandeis.edu | comments on Amerifone service |
16. Can you explain VoIP in a bit more detail?
What does "Internet Telephone" or "Voice Over IP (VoIP)" mean?
IP is an acronym for Internet Protocol. IP is a way of computers communicating between each other. Data is broken in to small groups called packets.
IP is what is called a routing protocol. It facilitates moving a packet of data by storing it and then forwarding it along a chain of computers until it reaches its destination. However sending a packet via IP does not guarantee that it will arrive at, or when it will arrive.
Due to differences in the way packets are routed, it is possible for packets to arrive in any sequence, i.e. just because a packet is the first sent out in a group, does not mean that it will be the first received.
An additional protocol called TCP (Transmission Control Protocol) is used on top of IP to make sure all the packets in a message arrive and they are used in the correct sequence. The overhead of using TCP is to high for real time voice so it is not used for VoIP.
Now a short lesson in physics. Sound travels in waves to your ear. Each wave has a width (pitch) and a height (loudness). Your ear works by the wave pushing a series of bones. As the bones move in and out, electrical impulses travel from your ear to your brain.
Your ear can only sense one pressure at a time. What you hear is pressure at any instant (in or out and intensity), interpreted by your brain as a sound our mixture of sounds.
If we measure the sound pressure and direction at any instant in time electronically, we have a digital picture of the sound wave. We can then take this digital picture send it over the computer or store it for later use. When we recreate the wave from it, out brain hears the original sound.
This is the basis of digital telephones, CDs, MP3s, etc. All take digital pictures of sound waves and move them around and recreate them later.
So if we combine the ability to take a digital picture of a sound wave, group these pictures into small groups, and send them over the Internet we have VoIP, voice over IP.
Various computing tricks have been used to make the packets smaller, or handle them if they come too late or out of sequence.
Does VoIP work? In a word "often". Since IP is a store and forward protocol, the amount of time it takes a packet to reach its destination varies from packet to packet. Many factors affect the time it takes (called latency), include how many other people are sending packets, the speed of the slowest connection in the chain, etc.
If you have a reliable connection with low latency, then VoIP will work for you. If your connection is not reliable or the latency is high, VoIP will be anywhere from annoying to useless.
In Israel Internet usage follows a very consistent pattern. On Sunday morning, no one uses the Internet and the latency to outside of Israel is low.As the day progresses, the usage goes up and latency increases. During the week it becomes worse and worse, peaking Saturday night.
Depending upon whom you are calling and when, VoIP may be for you.
17. What is PC-to-PC VoIP communication?
There are programs available that allow PC users to communicate with each other via the computers' microphone, speakers or headphones, or a headset. MSN Messenger, Yahoo Communicator, and Skype are well-known examples.
PC-to-PC VoIP is not covered extensively this document.
A "hardware phone" is a telephone with an ethernet or wifi connection that uses the SIP (session intiation protcocol) or Skype protocol.
Hardware phones are not covered extensively this document.
Soft(ware) phone: A software implementation of the SIP, Skype or other protocol that has the "look and feel" of a telephone.
ATA (analog telephone adaptor): a device that connects between a regular analog telephone and a network, usually etherenet) that converts the signals from and to the phone to SIP or another protocol. Most common are the Packet8 "box", Cisco ATA186 or Motorola units used by Vonage.
21. What are latency and jitter?
According to www.webopedia.com, latency is defined as, "In networking, the amount of time it takes a packet to travel from source to destination. Together, latency and bandwidth define the speed and capacity of a network."
Suppose you have a garden hose delivering water from the water spigot to your petunias. Latency is essentially the delay from when the water goes in one end of a hose and to when it comes out the other end. Even if the hose is very thick, that is, has a high bandwidth, the length of the hose determines how long it takes (the latency) to actually see the water begin to flow.
VoIP is a two way connection. Water has to go into the hose both at the spigot end and the petunia end, and it has to travel all the way through the hose. The hose has to be both thick enough to carry the required quantity of water and short enough so that you do not have to wait too long for the water (speech) to reach the other end.
So, if you have an Internet connection that goes across the Atlantic by bouncing off satellites at 23,500 miles above the earth numerous times, it stands to reason that the latency will be so high that there will be very noticable delays in hearing the voice from the other end.
Because voice is broken into packets and reassembled, it is possible that not all the packets are delayed by the same amount, a problem called jitter. Jitter can result in garbled speech.
The white paper Understanding Jitter in Packet Voice Networks (Cisco IOS Platforms) defines jitter as "a variation in the delay of received packets. Due to network congestion, improper queuing, or configuration errors, this steady stream can become lumpy, or the delay between each packet can vary instead of remaining constant." It goes on to say, "If the jitter is so large that it causes packets to be received out of the range of this buffer, the out-of-range packets are discarded and dropouts are heard in the audio. For losses as small as one packet, the DSP interpolates what it thinks the audio should be and no problem is audible. When jitter exceeds what the DSP can do to make up for the missing packets, audio problems are heard."
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