Panasonic KX-TDA0490, Getting Started

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A1 VoIP Requirements
46 Getting Started
A1 VoIP Requirements
A1.1 Bandwidth Assessment
When using the VoIP Gateway Card, you must ensure that the IP network in use has enough
bandwidth to support VoIP communications. If the amount of bandwidth required for VoIP
communications is larger than what the network can accommodate, speech quality will be
compromised. In addition, there may be some adverse effect on the performance of other applications
(e.g., email or web applications) that use the same network. Therefore, care must be taken when
assessing bandwidth requirements.
Inform your network administrator of the required bandwidth, and make sure that the network can
support VoIP communications even under conditions of maximum network traffic.
Bandwidth Calculation
Provided below is the formula to find out the amount of bandwidth required for VoIP communications:
Required bandwidth for one VoIP channel is shown in the tables below (for more details, refer to "2.2.3
Voice Communication Parameters" in the VoIP Gateway Card Programming Guide).
Required Bandwidth for One VoIP Channel
The required bandwidth depends on what combination of CODEC and packet sending interval is
used. Keep in mind the following points about the type of CODEC and packet sending interval, in
terms of the speech quality:
• The speech quality of the CODECs varies as follows: (High) G.711, G.729A, G.723.1 (Low)
• The shorter the packet sending interval, the higher the speech quality.
• The higher the speech quality the VoIP Gateway Card provides, the more bandwidth the
card requires.
Via LAN
Required Bandwidth
= (No. of Fax Machines × Required Bandwidth for the G.711 CODEC) +
[(16 - No. of Fax Machines) × Required Bandwidth for Voice Communication]
CODEC
Packet Sending Interval
20 ms 30 ms 40 ms 60 ms 90 ms
G.711 87.2 kbps 79.5 kbps 75.6 kbps 71.7 kbps —
G.729A 31.2 kbps 23.5 kbps 19.6 kbps 15.7 kbps —
G.723.1 5.3 kbps — 20.8 kbps — 13.1 kbps 10.5 kbps
G.723.1 6.3 kbps — 21.9 kbps — 14.1 kbps 11.6 kbps