Ip Trunk - (Sip) Session Initiation Protocol - NEC SL1000 Features And Specifications Manual

SL1000/SL1100 ISSUE 2.0

IP Trunk - (SIP) Session Initiation Protocol

Version 2.0 or higher software provides;
• When + is added to the country code of an incoming SIP trunk call, it is recognized as an
international call, simplifying outgoing calls from the incoming call list.
• The VAD feature is enhanced. The SL1000/SL1100 is able to offer VAD on negotiation of the SDP.
• To convert analog signal to Voice Band Data (VBD) over SIP Trunks.
Description
I
The SL1000/SL1100 IP Trunk SIP package sends the real time voice over the corporate LAN or WAN.
The voice from the telephone is digitized and then put into frames to be sent over a network using
Internet protocol.
Using VoIPDB equipment at a gateway (a network point that acts as an entrance to another network),
the packetized voice transmissions from users in the company are received and routed to other parts
of the company Intranet (local area or wide area network) or they can be sent over the Internet using
CO lines to another gateway.
Depending on the requirements and resource allocation in the LAN/WAN/Internet, the VoIPDB - SIP
can be configured to use any of the following voice compressions:
• G.711 μ-Law - Highest Bandwidth
• G.729 (a) - Most often used
• The LAN/WAN or Internet connection is provided by a 10 Base-T/100 Base-TX Ethernet.
VAD Enhancement (V2.0 or higher)
RTP voice data always transmitted during VoIP talking even if a user is not speaking. If VAD (Voice
activity Detection) is enabled in a system, the system can stop sending RTP voice data while a user is
not speaking.
VAD enable/disable is determined by only system data before V1.5. This enhancement improves this
VAD determination method by using SIP negotiation.
VBD on SIP Trunk (V2.0 or higher)
Voice Band Data (VBD) is what is called modem over IP. This feature enables use of VBD (Voice
Band Data) by System. If use VBD. Analog modem signal is converted into voice band data and can
be submitted via SIP Trunk.
For a list of vendors that have successfully completed interoperability certification go to http://
www.necntac.com and refer to Technical Documentation.
SIP Trunk E.164 Support (V2.0 or higher)
With the SIP Trunk E.164 Support enabled the PBX is able to support SIP configurations where the
number presentation within the SIP messages is formatted using the E.164 international numbering
scheme. Specifically the system is able to handle the '+' digit when required as the International
Access Code.
For example a normal international SIP call could be dialed and presented from the system as follows;
Number dialed = 00441202223344
Request-URI: Invite sip: 00441202223344@172.16.18.100 SIP/2.0
However with SIP Trunk E.164 Support enabled the SIP call could be presented once dialed as below;
Request-URI: Invite sip:+441202223344@172.16.18.100 SIP/2.0
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