User manual

3. Voice Encoding/Decoding settings (Codec Setting) allows
users to change the Voice Encoding/Decoding settings and
Network bandwidth to obtain the best voice performance with the
SIP phone. It is suggested that users retain the default settings
for optimum use.
Screen Shot 12.2.2-3
FPP: Frames per Packet
For example: The default frame length is 80 samples
(10 ms) based on an 8K sample rate, so if FPP of
G.711 is set to 2, that means a packet will contain
160 samples (20 ms).
Default frame length of G.729: 80 samples, 10 ms
Default frame length of G.723: 240 samples, 30ms
When you select a different bandwidth preference, the phone will use the Codec
according to the sequence:
High: G.711Ulaw, G.711Alaw, G.729, G.723 (currently do not support on the phone)
Medium: G.729, G.723,G.711Ulaw, G.711Alaw
Low: G.723, G.729, G.711Ulaw, G.711Alaw
Screen Shot 12.2.2-4
4. This setting is for advanced users and/or SIP phone service
operators only.
DTMF payload number according to RFC2833
Call prefix: The content in this field will be added in front of
number dialed. Some service providers require
special prefixes to access certain services.
Server type: The phone will perform special processes for some
servers. We use the content of this field to identify
the type of SIP servers.