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Voice over IP (VoIP)

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1. One of the SIP terminals sends of list of supported codecs.

2. The second SIP terminal deletes the codecs from the list which are not supported

and sends the shortened list back to the first SIP terminal.

The exchanged codec lists can be filtered by the OpenCom 100 communications

system, e.g. to limit bandwidth based on the VoIP profile activated for the connection

or for the terminal. Please note that the negotiation regarding codecs supported also

takes place for connections between SIP terminals and other terminals / subscribers.

For example, the OpenCom 100 communications system uses a pre-defined codec list

for a connection between an SIP terminal and a TDM port:

IP system phones or DECT over IP base stations participate in codec negotiation with

the VoIP profile configured respectively. If no common audio codec is determined

during negotiation, it will not be possible to establish the call connection.

Transparent codec interconnection

Transparent codec interconnection allows SIP terminals to use addition codecs even

though the desired codec is not, or not directly supported by the OpenCom 100 com-

munications system. Some examples are:

• G.722 audio codec for HQ audio

• H.264 video codec for transmitting images

Transparent codec interconnection is supported for internal SIP subscribers and in the

context of TC system networking with SIP tie line connections.

You have to create a special VoIP profile for completely unfiltered (transparent) codec

negotiation:

1. Open the Telephony: Extended: VoIP profile page in the configurator of the

OpenCom 100 communications system.

2. Click on the New button to create a new VoIP profile.

3. Activate the All codecs option. Enter a designation into the Profile name input

field. Use Apply to confirm.

Allocate this VoIP profile to the desired SIP terminal or to the desired SIP tie line.

Please note that bandwidth cannot be restricted for terminals or lines with this VoIP

profile. This is suitable, e.g. for SIP terminals operating on a LAN.

G.711a G.729 (if possible) RFC4733 DTMF

Aastra OpenCom 100 User Manual

Other manuals for Aastra OpenCom 100