TIPTEL 40 VoIP, Инструкция по установке и эксплуатации

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Internet telephony
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Note: Note that the RTP port range as well as port forwarding in your router
may have to be adjusted. The size of the RTP port range depends on
how many VoIP channels are configured. Two RTP ports have to be
reserved for each VoIP channel or ISDN-B channel.
RTP packet size
This setting allows you to determine how long the device collects all voice data
packets that are to be sent before actually sending them. The shorter this time frame,
the greater the necessary bandwidth. Reason: the voice data is sent in smaller
packets. For each packet, however, what is known as a header has to be calculated.
This header is sent less frequently in the case of larger voice data packets.
If, however, a larger voice data packet does not reach the recipient, this is noticeable
due to an acoustic interruption.
Dejitter buffer size
Jitter describes the time fluctuation between receiving two data packets. To
compensate for time fluctuations, a buffer (dejitter buffer) is employed. When setting
the size of the dejitter buffer, please keep the following effects in mind:
Too small a dejitter buffer can result in voice interruptions if data packages with a
longer runtime are rejected.
If the buffer is too large, there may be a perceptible echo.
Time between two dialing digits
Use this setting to influence the maximum amount of time that may pass between the
last input of a dialed number and the placing of the call.
Note: You can accelerate the placing of the call by pressing the # button after
entering the last digit.
QoS for SIP (TOS/DiffServ), QoS for RTP (TOS/DiffServ)
These settings allow you to influence the prioritization of voice data in the
network/Internet.