User's Manual

AirStream 4000/4001 WiMAX CPE User Manual

A few options are available in the drop down list of Port Select Mode in Group:

 Early Release First: the line which was released earliest receives an incoming call.

 Random: an incoming call is randomly dispatched to one of the lines.

 Order: an incoming call is dispatched to lines sequentially.

9.3.3 Call Timers

A few timers are defined in this section:

 Ringback Timer: A ringback tone, or audible ringing tone or ringback signal, is the audible ringing that

is heard on the telephone line by the calling party after dialing and prior to the call being answered at

the distant end. When A calls B from a CPE, if B does not answer the call, the “Ringback Timer”

defines the maximum waiting time after which the CPE should tear down the call, (if A does not hang

up the phone).

 Ring Timer: A ring tone is the sound made by a telephone to indicate an incoming call. When B calls A

at a CPE, if A does not answer the call, the “Ring Timer” defines the maximum waiting time after

which the CPE should tear down the call, (if B does not hang up the phone).

 Busy Timer: when A calls B, if B is busy, the “Busy Time” defines the maximum waiting time that the

CPE should tear down the call, (if A does not hang up the phone).

 Offhook Warning Time: The maximum waiting time after which the CPE should send warning signals

to the line.

9.4 DSP Configuration

Voice is sampled and coded into digital bit stream, before they are packetized into IP packets. The following

sections discuss various Codecs supported by the CPE

The parameters are explained in more details:

 DTMF Transfer Mode: DMTF stands for Dual-Tone Multi-Frequency (DTMF) signaling, which is used

for transfer of telecommunication signal over the line in the voice-frequency band in legacy PSTN

networks. In VoIP networks, legacy devices continues to use DMTF to send busy signal, Flash or

alphanumerical digits. For example, a user may be required to key in a password to join a conference

call, which is sent from legacy phone as DTMF signal, across the IX253P CPE, to the conference

bridge. There are a few ways to transport DMTF tones from legacy devices, over a VoIP network.

o Audio Stream: DTMF signals from legacy phones are packetized in RTP packets as audio

stream. Transporting DTMF user inputs as audio stream works well in a data network with