Aastra 470 System Manual page 52

Expansion Stages and System Capacity
Compared with DSP modules, modules with the designation DSPX are fitted with
more powerful DSP chips. They are used to transmit VoIP data among others using
the SRTP protocol (Secure VoIP).
Allocatable functions
One or more functions can be allocated to the individual DSP chips on the DSP
modules. For this the DSP chips have to be loaded with different firmware. The DSP
resources can be used for DECT telephony, Voice-over-IP, Voice Mail, hands-free op-
eration, integrated mobile phones or fax transmissions. This means that for each
DSP chip a specific number of voice channels is available for the corresponding
functions. Some of these functions are subject to a licence (see also
page 70).
• DECT
Operation of a DECT system on DSI interfaces with cordless phones. In the case
of connections between DECT and non-DECT endpoints the voice data has to be
converted. This process requires DSP capacity.
DECT channels can be used without a licence.
• VoIP
Connections between IP and non-IP endpoints are made via an IP media gate-
way. This is carry out by the integrated standard media switch that switches VoIP
channels for call connections in the IP network. The Standard Media Switch uses
DSP resources for the real-time processing of the call data. VoIP channels are al-
ways required between IP and non-IP endpoints, e.g. for internal connections
between an SIP/IP phone and a digital system phone or e.g. for an external user
who is routed to the internal Voice Mail System via an SIP network interface. In
an AIN VoIP channels are also used for call connections between the nodes (see
"Use of VoIP channels", page 54
The number of configurable VoIP channels depends on both the type of DSP
chip (see "Configuration of DSP chips", page
"Standard Media Switch modes of operation", page
If the VoIP mode is set to G.711, two G.711 VoIPchannels per system can be used
without a licence. One
quired for each additional VoIP channel.
Note
the IP media gateway function can also be provided with IP media
modules. The necessary DSP resources are located on the IP media
modules themselves. Standard media switch and IP media switch are
independent of each other and can be used as a mix (see
modules", page
52
for an overview).
VoIP Channels for Standard Media Switch
58).
56) and the configured mode (see
55).
licence is re-
syd-0337/1.5 – R3.0 – 05.2013
"Licences",
"IP media
Aastra 470 ab R3.0