Atlantis Land A02-RAV260-W54 ユーザーズマニュアル

                                                                                                                            

VoIPMaster 260W 

        

 

107 

What is How does it 
work? 
 

Many years ago we discovered that sending a signal to 
a remote destination could have be done also in a digital 
fashion: before sending it we have to digitalize it with an 
ADC (analog to digital converter), transmit it, and at the 
end transform it again in analog format with DAC (digital 
to analog converter) to use it. 
VoIP works like that, digitalizing voice in data packets, 
sending them and reconverting them in voice at 
destination. 
Digital format can be better controlled: we can compress 
it, route it, convert it to a new better format, and so on; 
also we saw that digital signal is more noise tolerant 
than the analog one (see GSM vs TACS). 
TCP/IP networks are made of IP packets containing a 
header (to control communication) and a payload to 
transport data: VoIP use it to go across the network and 
come to destination. 
Voice (source) -- ADC ---- Internet --- DAC -- Voice 
(dest)

 

 

What is the 
advantages using 
VoIP rather PSTN? 
 

When you are using PSTN line, you typically pay for 
time used to a PSTN line manager company: more time 
you stay at phone and more you'll pay. In addition you 
couldn't talk with other that one person at a time. 
In opposite with VoIP mechanism you can talk all the 
time with every person you want (the needed is that 
other person is also connected to Internet at the same 
time), as far as you want (money independent) and, in 
addition, you can talk with many people at the same 
time. 
If you're still not persuaded you can consider that, at the 
same time, you can exchange data with people are you 
talking with, sending images, graphs and videos.