D glossary – CounterPath X-Lite 4.6 for Mac User Guide User Manual
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D Glossary
Broadband
Broad or wide bandwidth. In data transmission, the wider the band, the more data it is 
possible to transmit in a given time span. A cable, DSL and ADSL connection to the 
network provide broadband for data transmission. A dialup or ISDN connection 
typically provide a narrow bandwidth for data transmission.
Codec
The format by which audio or video streams are compressed for transmission over 
networks. Codecs can be categorized as either narrowband or wideband: Narrowband 
codecs work with low bandwidth such as a dialup internet connection. These codecs 
have a sampling rate of 8 kHz. Wideband codecs work with high bandwidths and 
result in better audio quality. However, they do not work with PSTN. These codecs 
have a sampling rate of 16 kHz.
Dial plan
The rules that X-Lite follows in order to interpret the softphone address or phone 
number that the user has entered and to modify the number or address, as required, to 
ensure that the call will be placed successfully. 
DTMF
Dual-tone multi frequency. DTMF is the system that is used in interactive voice-
response menu systems such as the menu system for accessing voicemail messages. 
The DTMF system allows the user to interact with the menu by pressing keys on a 
dialpad or keyboard.
Firewall
A technology that prevents unauthorized people connecting to your computer and to 
the applications running on the computer.
IM
Instant Messaging. A technology that lets users send text message and files for near 
instantaneous delivery and display on each others’ computers.
MWI
Message Waiting Indicator. An indicator that there is a voicemail message for the 
owner of an account.
Narrowband
In data transmission, the wider the band, the more data it is possible to transmit in a 
given time span. A cable, DSL and ADSL connection to the network provide 
broadband for data transmission. A dialup or ISDN connection typically provide a 
narrow bandwidth for data transmission.
Presence
An instant messaging feature that allows users to share information about their online 
status.
PSTN
Public Switch Telephone Network. The traditional land-line phone network.
SIP account
An account that provides the user the ability to make VoIP phone calls. The account 
encapsulates the rules and functions the user can access.
Softphone address
The address used to connect to a SIP endpoint. In other words, the “phone number” 
used in a VoIP phone call. For example, sip:[email protected].
USB device
Universal Serial Bus device. A device that follows a specific communications VoIP
Voice over Internet Protocol. A variation of IP used for sending voice data over the 
internet, in other words, used for making phone calls over the internet.
VoIP service provider
A business that provides a VoIP service, allowing a user to connect to the internet in 
order to make VoIP phone calls using X-Lite. The VoIP service provider sets up a SIP 
account for the user.