124
AdminGuide-Voss12-1.docx
Glossary
■
A-law
A-law is a standard companding algorithm, used in European digital
communications systems to optimize, i.e,. modify the dynamic range of an analog
signal for digitizing. It is similar to the µ–law algorithm used in North America and
Japan.
■
ANI(Automatic Number Identification)
This a feature of telephony intelligent network services that permits subscribers to
display the telephone number of calling parties. The ANI type is depends on
telephone service provider. Sometimes, this service is delivered with DTMF tone.
■
CODEC(Coder-DECoder)
A codec is a device or program capable or encoding and/or decoding a digital data
stream or signal. This can be used in audio data compression (ex. G729 CODEC).
■
Channel
Channel a media or equipment which controls data transmission between two
equipments. Channel is more like logical link than physical link so even if there is
only one physical link exists as communication line there can be more than one of
logical links.
■
CNG (Comfort Noise Generation)
While using VAD, users cannot hear any sound due to not sending voice packet to
the other party. In that case, users will be confused whether the call is disconnected
or not, so artificial background noise will be filled the silence to let the other party
know the call is not disconnected.
■
DHCP (Dynamic Host Configuration Protocol)
DHCP is a protocol used by networked devices to obtain various parameters
necessary for the clients to operate in an internet protocol network. This protocol
assigns an IP address to a PC for temporary so it can be said as IP address lease.
Therefore, if available IP addresses are less than computers, this scheme optimize
using IP address by assigning each IP address for short time.
■
DSP (Digital Signal Processor)
A specialized microprocessor designed especially for digital signal processing,
generally used in voice or video real-time computing.
■
DTMF (Dual Tone Multi Frequency)
This signaling is used for telephone signaling over the line in the voice frequency
band to the call switching center. DTMF is a signal which is generated when digital
phone button was pressed then this signal is sent to Central Office (CO). Each key
on a DTMF applied phone generates two tones which have dedicated frequency.
Therefore, this tone is designed to not be copied by human voice so one tone
belongs to high frequency and another tone belongs to low frequency.
■
Delay Start
It is a type of PSTN signaling. Call is started after sender occupies a corresponding
PSTN line. Off-Hook Status of PBX at receiver’s side continues until it’s ready to
receive. When the status of the PBX is ready, its status turns to On-Hook. Then, the
PBX at sender’s side sends digits to the PBX at receiver’s side. And, then, the PBX