User's Manual  1066  Document #: LTRT-27055 
 
  Mediant 1000B Gateway & E-SBC 
Parameter  Description 
case, early media is played to the ISDN side and then the ringback 
tone is played by the IP PBX. 
  [1] = Enable. If the device sends a 183 response with SDP (due to 
a received ISDN Progress or Proceeding with PI messages) and 
an Alerting message is then received from the ISDN side (with or 
without Progress Indicator), the device does not send a 180 
Ringing response to the caller and the voice channel remains 
open. Therefore, in this case, early media is played to the ISDN 
side and a ringback tone is not played by the IP PBX. 
Note: 
  The parameter is applicable only to digital interfaces. 
  The parameter is applicable only if the EnableEarlyMedia 
parameter is set to 1 (i.e., enabled). 
183 Message Behavior 
configure voip > sip-
definition settings > 183-
msg-behavior 
[SIP183Behaviour] 
Digital: Defines the ISDN message that is sent when the 183 Session 
Progress message is received for IP-to-Tel calls. 
Analog: Defines the response of the device upon receipt of a SIP 183 
response. 
  [0] Progress = (Default)  
  Digital: The device sends a Progress message. 
  Analog: A 183 response (without SDP) does not cause the 
device to play a ringback tone. 
  [1] Alert =  
 
Digital: The device sends an Alerting message (upon receipt of 
a 183 response) instead of an ISDN Progress message. 
  Analog: 183 response is handled by the device as if a 180 
Ringing response is received, and the device plays a ringback 
tone. 
Note: The parameter is applicable only to the Gateway application. 
[ReleaseIP2ISDNCallOnPro
gressWithCause] 
Typically, if an Q.931 Progress message with a Cause is received 
from the PSTN for an outgoing IP-to-ISDN call and the 
EnableEarlyMedia parameter is set to 1 (i.e., the Early Media feature 
is enabled), the device interworks the Progress to 183 + SDP to 
enable the originating party to hear the PSTN announcement about 
the call failure. Conversely, if EnableEarlyMedia is set to 0, the device 
disconnects the call by sending a SIP 4xx response to the originating 
party. However, if the ReleaseIP2ISDNCallOnProgressWithCause 
parameter is set to 1, then the device sends a SIP 4xx response even 
if the EnableEarlyMedia parameter is set to 1. 
  [0] = (Default) If a Progress with Cause message is received from 
the PSTN for an outgoing IP-to-ISDN call, the device does not 
disconnect the call by sending a SIP 4xx response to the 
originating party. 
  [1] = The device sends a SIP 4xx response when the 
EnableEarlyMedia parameter is set to 0. 
  [2] = The device always sends a SIP 4xx response, even if he 
EnableEarlyMedia parameter is set to 1. 
Note: The parameter is applicable only to digital interfaces. 
Session-Expires Time 
configure voip > sbc settings 
> session-expires-time 
[SIPSessionExpires] 
Defines the numerical value sent in the Session-Expires header in the 
first SIP INVITE request or response (if the call is answered). 
The valid range is 1 to 86,400 sec. The default is 0 (i.e., the Session-
Expires header is disabled).