List of parameters – 2N Helios IP Configuration Manual v2.8 User Manual

Page 62

Explanation of IP Telephony Terms

SIP

– is a phone call signalling transmission

(Session Initiation Protocol)

protocol used in IP telephony. It is primarily used for setting up, terminating and
forwarding calls between two SIP devices (the intercom and another IP phone in
this case). SIP devices can establish connections directly with each other (Direct
SIP Call) or, typically, via one or more servers: SIP Proxy and SIP Registrar.
SIP Proxy – is an IP network server responsible for call routing (call transfer to
another entity closer to the destination). There can be one or more SIP Proxy
units between the users.
SIP Registrar – is an IP network server responsible for user registration in a
certain network section. As a rule, SIP device registration is necessary for a user
to be accessible to the others on a certain phone number. SIP Registrar and SIP
Proxy are often installed on one and the same server.
RTP

– is a protocol defining the standard

(Real-Time Transport Protocol)

packet format for audio and video transmission in IP networks. 2N Helios IP

uses the RTP for audio and video stream transmission during a call. The stream
parameters (port numbers, protocols and codecs) are defined and negotiated via
the SDP (Session Description Protocol).

The

intercoms support three ways of SIP signalling:

2N Helios IP

via the

(

), which is the most frequently used

User Datagram Protocol

UDP

unsecured signalling method
via the

, which is less frequent, yet

Transmission Control Protocol ( TCP)

recommended unsecured signalling method
via the

protocol, where SIP messages are

Transaction Layer Security (TLS)

secured against third party monitoring and modification

List of Parameters

The

Phone settings are arranged in five tabs:

2N Helios IP

SIP 1 and SIP 2 – complete SIP terminal settings
Calls – incoming and outgoing call settings
Audio – audio codec, DTMF transmission and other audio stream transmission
settings
Video – video codec, video resolution and other video stream transmission
settings