ZyXEL Communications NVG2053, Руководство пользователя

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Chapter 17 Voice
NVG2053 User’s Guide
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17.1.2 What You Need to Know
VoIP
VoIP stands for Voice over IP. IP is the Internet Protocol, which is the message-
carrying standard the Internet runs on. So, Voice over IP is the sending of voice
signals (speech) over the Internet (or another network that uses the Internet
Protocol).
SIP
SIP stands for Session Initiation Protocol. SIP is a signalling standard that lets one
network device (like a computer or the NVG2053) send messages to another. In
VoIP, these messages are about phone calls over the network. For example, when
you dial a number on your NVG2053, it sends a SIP message over the network
asking the other device (the number you dialed) to take part in the call.
SIP Accounts
A SIP account is a type of VoIP account. It is an arrangement with a service
provider that lets you make phone calls over the Internet. When you set the
NVG2053 to use your SIP account to make calls, the NVG2053 is able to send all
the information about the phone call to your service provider on the Internet.
Strictly speaking, you don’t need a SIP account. It is possible for one SIP device
(like the NVG2053) to call another without involving a SIP service provider.
However, the networking difficulties involved in doing this make it tremendously
impractical under normal circumstances. Your SIP account provider removes these
difficulties by taking care of the call routing and setup - figuring out how to get
your call to the right place in a way that you and the other person can talk to one
another.
How to Find Out More
See Chapter 2 on page 27 for a tutorial showing how to set up these screens in an
example scenario.
See Section 17.9 on page 183 for advanced technical information on SIP.
17.2 Before You Begin
• Before you can use these screens, you need to have a VoIP account already set
up. If you don’t have one yet, you can sign up with a VoIP service provider over
the Internet.