Grandstream Networks HT-496 User Manual page 24

Send Flash Event
Enable Call Features
Use Bell-style 3-way
Conference
Off-hook Auto-Dial
Proxy-Require
Disable Call Waiting
NAT Traversal (STUN)
No Key Entry Timeout
Preferred Vocoder
Voice Frames per TX
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modes supported: 1) in audio which means DTMF is combined in audio signal
(not very reliable with low-bit-rate codec), 2) via RTP (RFC2833), or 3) via SIP
INFO. Multiple selections of DTMF method are supported.
Default is No. If set to yes, flash will be sent as DTMF event.
Default is Yes. Advanced call features and feature codes functions are
supported locally.
Enables Bellcore Style 3-way Conference if parameter is set to "Yes". *23 is
disabled.
This parameter automatically configures and dials User ID or extension
number upon off-hook. Only the user part of a SIP address needs is entered
here. The HT–496 will automatically append the "@" and the host portion of
the corresponding SIP address.
SIP Extension to notify SIP server that the unit is behind the NAT/Firewall.
Default is No.
This parameter defines whether the HT–496 NAT traversal mechanism is
activated or not. If activated (by choosing "Yes") and a STUN server is also
specified, then the HT–496 performs according to the STUN client
specification. Under this mode, the embedded STUN client will detect if and
what type of firewall/NAT is used. If the detected NAT is a Full Cone,
Restricted Cone, or a Port-Restricted Cone, the HT–496 will use its mapped
public IP address and port in all of its SIP and SDP messages.
If the NAT Traversal field is set to "Yes" with no specified STUN server, the
HT–496 will periodically (every 20 seconds or so) send a blank UDP packet
(with no payload data) to the SIP server to keep the "hole" on the NAT open.
Default is 4 seconds.
The HT–496 supports up to 6 different Vocoder types including G.711 A-/U-
law，G.723.1, G.726, G.729A/B, iLBC.
Users can configure Vocoders in a preference list included with the same
preference order in SDP message. The first Vocoder in this list is the
appropriate option in "Choice 1". The last Vocoder in this list is the appropriate
option in "Choice 6".
Number of voice frames transmitted in a single packet. User should be aware
of the requested packet time (used in SDP message). This parameter is
associated with the first vocoder in the Vocoder Preference List or the actual
payload type negotiated between the 2 conversation parties at run time.
e.g. if the first vocoder is configured as G.723 and the "Voice Frames per TX"
is set to 2, then the "ptime" value in the SDP message of an INVITE request
will be 60ms because each G.723 voice frame contains 30ms of audio.
If the configured voice frames per TX exceeds the maximum allowed value,
the HT–496 will use and save the maximum allowed value for the
corresponding first vocoder choice.
The maximum value for PCM is 10(x10ms) frames;
•
for G.726, it is 20 (x10ms) frames; .
•
for G.723, it is 32 (x30ms) frames;
HT–496 User Manual
Firmware 1.0.3.64
sales@voipon.co.uk Tel: +44 (0)1245 808195
Page 24 of 33
Last Updated: 1/2007
Fax: +44 (0)1245 600030