Analogue Telephone Adaptor
A hardware device that converts the signals from a standard analogue
telephone into the digital signals that a VOIP device needs to communicate over the
Asterisk is a complete PBX software. It runs
on Linux and provides all of the features you would expect from a PBX and
more. Asterisk does voice over IP in three protocols, and can
interoperate with almost all standards-based telephony equipment using
relatively inexpensive hardware. For more information, refer to www.asterisk.org
Broadband is the next generation of internet
connectivity that allows users to get fast access to any data on the
internet. Broadband includes cable and ADSL internet connections. VoIP
needs broadband to operate at a minimal Quality of Service that is
acceptable to most people. Information about broadband is available on
this site on the broadband
This is where the identity (number) of an incoming telephone caller is
displayed on a compatable telephone handset . If the receiver of the
telephone call knows the caller and has the caller’s phone number
programmed into their compatible handset, the name of the caller can also
be displayed on the handset.
The Dynamic Host Configuration Protocol (DHCP) is
an internet protocol that automates the allocation of ip addresses for
computers that use TCP/IP (and yours does otherwise you wouldn’t be reading this).
Direct Inward Dialling Number
This is a telephone number that you can give to other people to phone
you. Not all VSPs will give you a DID. All DIDs in Australia are
registered with Telstra, and Telstra charges VSPs $5.00 per month for
each DID. The VSP will then charge you $5.00 if you want a DID. Not
everyone that uses VoIP will need a DID (ie if you keep your normal PSTN
phone number and only use VoIP for outgoing calls).
Telephone Electronic Number Mapping is a system
where anyone that has a PSTN phone or a DID can register their phone number on an
international database of VoIP users. Whenever someone with a VoIP
telephone service (from a participating VSP) calls a phone number using
their VoIP service, their participating VSP first checks the ENUM
database. Information about ENUM is available on this site on the
A firewall protects your computer network from
the internet by preventing network traffic communicating between each
other. That’s great to prevent malicious attacks however it can cause
havoc if you are trying to get your ip telephone to work. All routers
have a firewall built in. Information about routers is available on this
site on the routers page.
The Internet Protocol Address is a unique
number that is used to identify a hardware device on a network (NB The
biggest network in the world is the Internet itself). An IP address takes
the form ###.###.###.### where # = any integer. IP Addresses are
allocated by routers so that the router knows what hardware devices are
connected to it.
Internet Service Provider (ISP)
A company (ie like
Telstra BigPond, Optusnet) that provides internet service to a subscriber
(ie you). An ISP physically connects to the internet by paying for a
connection to one or more internet service providers. The ISP then allows
you to connect to their network and in doing so connects you to the
a 12 digit HEX number that uniquely
identifies computer hardware that connects to the internet.
Private Branch Exchange
Port (telephone numbers)
Every telephone number in
Australia is related to a particular telephone company. When you change
your telephone company, you can take your telephone number with your by
trans(port)ing the number with you. This service is available between
Optus, Vodaphone, Telstra and Virgin, but is currently not available
Plain Old Telephone Network
Used interchangably with PSTN to describe the standard telephone network.
Public Switched Telephone
This is the standard telephone network that we all grew up with (ie
Telstra, Optus etc).
Quality of Serivice
Quality of Service is a software inclusion in many routers that allows
the user to prioritise the upstream bandwidth for a particular device. In
this way, you can give a device such as an ATA priority over other
internet traffic so that the quality of the VoIP call is maintained. This
is important because most broadband connections have a smaller upstream
bandwidth than the downstream bandwith. Information about QoS is
available on this site on the Routers page.
A router is effectively a ‘powerboard’ for the
internet. You can connect more than one internet device to your single
internet connection. Almost certainly if you have started with broadband
internet, and then decided to add VoIP to your suite of internet
services, you will need to buy a router. Information about routers is
available on this site on the routers page.
Real Time Protocol
Session Initiation Protocol is the world wide
standard used to initiate voice and video connectivity between 2 or more
users. SIP is the protocol used to ‘invite (or ring)’ another VOIP user to talk to you.
Skype is a PC based VoIP service that uses a
propriatry protocol. This means that Skype users can only phone other
Skype users, and they cannot make calls to the PSTN network. For more information go to
A software based telephone that allows your
PC to act like a regular telephone handset. Engin has a softphone that
can be used with its VoIP service.
Simple Traversal of UDP through
Different routers handle NAT differently. Which method your router uses
will have an impact on how your ATA needs to operate. Some ATAs have a
STUN client built in. Therefore your ATA can send a message to a STUN
server and get a response back. This process called Stunning will tell
the ATA what the public IP address of the ATA is, and how the Router is
passing packets between the ATA and the internet.
Time Division Multiplexing
Voice Over Internet Protocol
VoIP is a protocol the specifies how data is sent and received across the
internet. VoIP uses codecs
to code and decode the analogue data
from your microphone into digital packets of data . The data is first
coded into packets (ie descreet snippets of your conversation), then
trasmitted across the internet using the voice over internet protocol,
and then decoded and joined together again back into the continuous
conversation so the person on the other end can hear you normally.
VoIP Service Provider
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