Viii. specify codec – AirLive ePhone-2000S User Manual
Page 21
AirLive ePhone-2000S
English Version
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(1) To determine whether you are currently NATed or behind a firewall
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Go to 『Main Menu』=>『6.Network』/『4.NAT & firewall』/『1.STUN』 and
configure your STUN server in “1.STUN server”, such as “Sip.com” (IP SIP
Phone will try to locate the STUN server of “Sip.com” domain via DNS SRV
query (_stun._udp.Sip.com) or “STUN.Sip.com” (61.222.26.124) (explicitly
specify the STUN server). Press 【HOLD】to confirm.
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Go to 『Main Menu』=>『6.Network』/『4.NAT & firewall』/『1.STUN』/
『
2. Diagnose NAT』to detect your NAT type. If the diagnosis is one of the
following, you could consider enable STUN as a way to traverse NAT;
otherwise you should adopt option-1.
1.
Public internet (Neither NAT nor Firewall is involved)。
2.
Symmetric UDP Firewall
3.
Full cone NAT
4.
Restricted cone NAT
5.
Port restricted cone NAT
(2) Activate STUN Mode
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『
Main Menu』=>『6.Network』/『4.NAT & firewall』/『2.UDP traversal』
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Choose ”3.Enable STUN” and press 【HOLD】to confirm.
Note: the STUN server configured into 『6.Network』/『4.NAT & firewall』/『1.STUN』
/『1.STUN server』must be functional and reachable for STUN to work.
VIII. Specify CODEC
The CODECs available on the phone includes G.711A (64kbps), G.711μ (64kbps),
G.729A/G.729AB (8 kbps), G.723.1/G.723.1A (both 5.3 and 6.4 kbps). The default
preference is to prioritize them based on their compressed voice quality: the higher quality it
is, the higher priority it will be. That is, the default CODEC preference is G.711A, G.711μ,
G.729A then G.723.1A (in that order).
High quality comes in a price: it consumes more precious bandwidth. Take G.711μ for
example, it takes as much as 64 kbps per call, as opposed to 5.3 kbps if G.723.1A is
employed. Thus, if you have limited bandwidth for VoIP, you should consider prioritize
those CODECs come with lower bit-rates such that it will use the most preferred CODEC on
making/taking calls.
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To set up personal CODEC preference by keypad or TELNET:
『Main Menu』=>『8.Advanced』/『1.CODEC』/『1.Preferences』
Reorder the CODEC precedence：
0: Disable the selected CODEC
1: Highest priority
8: Lowest priority