ZyXEL MAX318M User Guide - Page 164

Chapter 10 The VoIP Account Screens Table 72 SIP (continued) LABEL 1st Codec, 2nd Codec, 3rd Codec DESCRIPTION Select the WiMAX Device's first, second, and third choices of the type of voice coder/decoder (codec) that you want the phone line to use when communicating with the SIP server. The following codecs (shown in highest quality to lowest quality order) are supported by the WiMAX Device: • G.711 aLaw (typically used in Europe) • G.711 muLaw (typically used in North America and Japan) • G.729 You can also select NONE for the 2nd and 3rd codecs if your VoIP service provider only gave you one or two codec settings. Session Timer Min Session Timer When two SIP devices start a SIP session, they must agree on a codec. Enter the minimum session expiry time in seconds. The allowable range is 90~65535 seconds. Session Timer When an incoming call requests a session expiry time that is lower than this value, the WiMAX Device will respond with a "423 session timer too small" message and tell the peer to use this value as the minimum bound. Enter the session expiry time in seconds for all phone connections on this trunk. The allowable range is 120~65535 seconds. This value cannot be lower than the Min Session Timer. The WiMAX Device will use INVITE or UPDATE method to keep alive a session every half of the session expiry time during a call. If the keep-alive action is successful, the WiMAX Device will re-start the timer and do another keep-alive action after it reaches half of the session expiry time. If the keep-alive action failed, the call will terminate automatically. See Section 9.4 on page 155 to configure the Refresh Method with the INVITE or UPDATE method. 164 WiMAX Device Configuration User's Guide