Seven frequently asked questions about
VoIP
1
. What is VoIP?
2.Why should I
care?
3.How does it
work?
4.So what do I
need?
5.What about
Skype?
6.What about
calls between VoIP and ordinary telephones?
7.What are
E-numbers?
1. What is VoIP?
VoIP stands for
Voice over Internet
Protocol. It is a way of making telephone calls over the
internet.
2. Why should I
care?
Fairly soon
even the telephone network will use the Internet Protocol to
send messages. In essence, there will be no distinction between the
internet and the telephone system.
Until then, VoIP calls may be free or cheaper than ordinary
phone calls.
3. How does it work?
It works much the same way as the telephone system, except for
how the message gets from your handset to the person you are
calling.
The phone system sets up an exclusive circuit between you and
the person you dial for the duration of the call. (That's why you
get an engaged signal when you dial someone who is already on the
line.) You speak into a microphone which converts the sound into
electrical waves that pass along the wires to the receiver, where
they are turned back into sound. With ISDN, a digital telephone
technology, the sounds are converted into digital packets but the
network sets up the exclusive circuit while the call lasts.
With VoIP, the sounds are converted into packets of digital
information, each with the internet address of the person you want
to speak to. Devices called network routers (rather than telephone
exchanges) send the individual packets around the network using the
easiest, quickest route. At their destination, the packets are put
back into the correct order and converted back into sound.
4. So what do I
need?
Individuals need a personal computer or a VoIP-capable
handset,
an internet connection, and the right software. Companies may have
a VoIP-capable PABX or message
server that has the right software.
5. What about Skype?
Skype is probably what most
people think of when they think of VoIP. Although Skype uses VoIP
to route data packets, it relies on peer-to-peer links between end
users' computers rather than network servers. How it does this is a
company secret.
The telecommunications industry is going for an international
standard, the
Session
Initiation Protocol (SIP). This is likely to become the global
standard for all digital multimedia calls. Despite its millions of
users, Skype will have to coexist with SIP rather than the other
way round. But Skype is free, so there's no harm in trying it
out.
6. What about calls between VoIP
and ordinary telephones?
SIP and Skype both allow this. Under SIP, you will probably pay
for the entire call unless it is to a subscriber on the same
network as yours. All Skype calls are free as long as they are to
other Skype users. Skype charges a small fee for calls to phones
outside its family.
7. What are
E-numbers?
E-numbers is this context are not shorthand for permissible food
additives.
The internet community is finalising its
E-Numbers plan.
This will give all VoIP devices a real telephone number that you
can call from any other phone.
Other useful VoIP links
ITSPA: The trade
industry website for the Internet Telephony Service Providers
Association
Voip-Info.org - a
reference site for all things VoIP. A wiki-style website which
covers everything to do with VOIP, including software, hardware,
service providers, reviews, configurations, standards, tips &
tricks and everything else related to voice over IP networks, IP
telephony and Internet Telephony.
CommsWatch:
A telecoms blog written by Roger Darlington
VoIP Watch: Andy
Abramson's VoIP blog
Voice Over Internet
Protocol - a US government website that is a great resource
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