Glossary
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at receiver’s side calls the destined subscriber. The subscriber picks up the phone,
then it turns to Off-Hook status. And then, communication line is connected to start
conversation, after the subscriber at the sender’s side keeps Off-Hook status to
continue conversation. Then, if a subscriber of any side hangs up, the line status
turns to On-Hook. And, then, the call is terminated.
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E.164
E.164 is an ITU-T recommendation which defines the international public
telecommunication numbering plan used in the PSTN and some other data network.
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Echo Cancellation
Echo Cancellation is a process of removing echo from a voice communication.
Normally, echo is generated by the difference of impedance on telephone network.
Echo Canceller saves just sent voice sample and if the voice returns apposite way,
the original voice can be traced by comparing with saved voice.
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Echo Suppressor
A Telecommunications device used to reduce the echo heard on long telephone
circuits.
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FXO (Foreign eXchange Office)
FOX is a telephone signaling interface that receives POTS(Plain Old Telephone
Service) from a Central Office(CO) of the Public Switched Telephone
Network(PSTN). In other words and FXO interface points to the Telco Office. It
generates the on-hook and off-hook indicators used to signal a loop closure at the
FSX’s end of the circuit. Analog telephone handsets, fax machines and modems are
FOX devices.
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FXS (Foreign eXchange Station/Subscriber)
FXS is a telephone interface delivers POTS service from the local phone
company’s Central Office(CO) and must be connected to subscriber equipment. In
other words, and FXS interface points to the subscriber. An FXS interfaces
provides sends dial tone, and generates ringing voltage.
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FTP (File Transfer Protocol)
FTP is a network protocol used to transfer data from one computer to another
through a network, such as over the internet.
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SNMP (Simple Network Management Protocol)
SNMP is used in network management system to monitor network attached devices
for conditions that warrant administrative attention. SNMP is a component of the
Internet Protocol Suite as defined by the IETF. It consists of a set of standards for
network management, including and application
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VAD (Voice Activity Detection)
A technique used in speech pressing wherein the presence or absence of human
speech is detected in regions of audio. The main uses of VAD are in speech coding
and speech recognition. It can facilitate speech processing, and can also be used to
deactivate some processes during non-speech segments; it can avoid unnecessary
coding/transmission of slience packet in VoIP, saving on computation and on
network bandwidth.
On the other hand, clipping, that is the loss of milliseconds of active speech, should
be minimized to preserve quality.
