Chapter 21 Product Specifications
User’s Guide
246
SIP ALG Your device is a SIP Application Layer Gateway (ALG). It
allows VoIP calls to pass through NAT for devices behind it
(such as a SIP-based VoIP software application on a
computer).
Dynamic Jitter Buffer The built-in adaptive buffer helps to smooth out the
variations in delay (jitter) for voice traffic (up to 60 ms). This
helps ensure good voice quality for your conversations.
Voice Activity Detection/
Silence Suppression Voice Activity Detection (VAD) reduces the bandwidth that a
call uses by not transmitting when you are not speaking.
Comfort Noise Generation Your device generates background noise to fill moments of
silence when the other device in a call stops transmitting
because the other party is not speaking (as total silence
could easily be mistaken for a lost connection).
Echo Cancellation You device supports G.168 of at least 24 ms.
This an ITU-T standard for eliminating the echo caused by the
sound of your voice reverberating in the telephone receiver
while you talk.
Time and Date Get the current time and date from an external server when
you turn on your WiMAX Modem. You can also set the time
manually.
Logging Use the WiMAX Modem’s logging feature to view connection
history, surveillance logs, and error messages.
Codecs Enhanced Variable Rate Codec (EVRC), G.711 (PCM µ-law
and a-law), G.729a, and G.723.1
Fax Support T.38 FAX relay (FAX over UDP).
G.711 fax relay for fax calls and be able to renegotiate codec
to G.711 if a fax call is detected.
Ring Tones Supports different distinctive ring tones on each line.
Call Prioritization Prioritize VoIP traffic originating from the RJ-11 ports over
any other traffic.
Table 111 Standards Supported STANDARD DESCRIPTION
RFC 768 User Datagram Protocol
RFC 791 Internet Protocol v4
RFC 792 Internet Control Message Protocol
RFC 792 Transmission Control Protocol
RFC 826 Address Resolution Protocol
RFC 854 Telnet Protocol
RFC 1349 Type of Service Protocol
RFC 1706 DNS NSAP Resource Records
RFC 1889 Real-time Transport Protocol (RTP)
RFC 1890 Real-time Transport Control Protocol (RTCP)
RFC 2030 Simple Network Time Protocol
Table 110 Firmware Specifications (continued)FEATURE DESCRIPTION