User's Manual

AirStream 4000/4001 WiMAX CPE User Manual

good quality. However, in networks with poor quality, packet losses or disordered delivery of

RTP packet may cause error. An alphanumerical digit input by the caller may be interpreted

wrongly as another digit.

o RFC2833: As a second option, the CPE can recognize the tones and translate them into a

name, such as numeric input, or Flash. RFC2833 defined payload format for named telephone

events, such as numeric input, or Flash.

o Signal: means the DTMF tones are translated to application level parameters such as SIP.

 Echo Cancellation: can be turned ON or OFF.

 Silence Suppression: can be turned ON or OFF.

 DSP Gain: Default value is 0. It may be adjusted to increase or decrease voice volume.

 Supported Codec: IX253P CPE supports automatic negotiation of codec with the network. The

Supported codecs, namely PCMa, PCMu, G.726, G.723, and G.729, are announced to the called party in

SIP Invite messages.

 Preferred Codec: Preferred Codec should be chosen in line with service provider’s strategy.

 Packetization Period: The period that a voice bit stream is packetized into an IP packet. The shorter the

period, the less delay of voice. Typical values are 5, 10, 20 milliseconds.

 G723 Rate: G723 supports two encoding data rate. This option allows the choices of encoding rate

using G.723 encoders.

 RFC2833 Payload: The payload value to send DMTF tones according to RFC2833.

 FSK Type: Frequency-shift keying (FSK) is a form of frequency modulation in which the modulating

signal shifts the output frequency between predetermined values. DTMF is one of the FSK applications.

It supports BellCore, ETSI, NTT options.