Version 7.2  1187  Mediant 500L Gateway & E-SBC 
 
User's Manual   69. Configuration Parameters Reference 
Parameter  Description 
an ISDN Alert with PI = 8 (unless the 
ProgressIndicator2ISDN_x parameter is configured 
differently). 
2)  If the LocalISDNRBSource parameter is set to 0, the 
device doesn't play a ringback tone and an Alert 
message without PI is sent to the ISDN. In this case, 
the PBX / PSTN plays the ringback tone to the 
originating terminal. Note that the receipt of a 183 
response does not cause the device configured for 
ISDN to play a ringback tone; the device issues a 
Progress message (unless SIP183Behaviour is set to 
1). If the SIP183Behaviour parameter is set to 1, the 
183 response is handled the same way as a 180 
Ringing response. 
  [2] Prefer IP = (Default): 
  Analog Interfaces: Plays a ringback tone to the Tel side 
only if a 180/183 response without SDP is received. If 
180/183 with SDP message is received, the device cuts 
through the voice channel and doesn't play the ringback 
tone. 
  Digital Interfaces: Plays according to 'Early Media'. If a 
SIP 180 response is received and the voice channel is 
already open (due to a previous 183 early media 
response or due to an SDP in the current 180 
response), the device doesn't play the ringback tone; PI 
= 8 is sent in an ISDN Alert message (unless the 
ProgressIndicator2ISDN_x parameter is configured 
differently). 
ISDN: The device operates according to the 
LocalISDNRBSource parameter: 
1)  If LocalISDNRBSource is set to 1, the device plays a 
ringback tone and sends an ISDN Alert with PI = 8 to 
the ISDN (unless the ProgressIndicator2ISDN_x 
parameter is configured differently). 
2)  If LocalISDNRBSource is set to 0, the device doesn't 
play a ringback tone. No PI is sent in the ISDN Alert 
message (unless the ProgressIndicator2ISDN_x 
parameter is configured differently). In this case, the 
PBX / PSTN plays a ringback tone to the originating 
terminal. Note that the receipt of a 183 response results 
in an ISDN Progress message (unless 
SIP183Behaviour is set to 1). If SIP183Behaviour is set 
to 1 (183 is handled the same way as a 180 + SDP), th
device sends an Alert message with PI = 8, without 
playing a ringback tone. 
  [3] Play Local Until Remote Media Arrive = Plays a ringback 
tone according to received media. The behaviour is similar 
to [2]. If a SIP 180 response is received and the voice 
channel is already open (due to a previous 183 early media 
response or due to an SDP in the current 180 response), 
the device plays a local ringback tone if there are no prior 
received RTP packets. The device stops playing the local 
ringback tone as soon as it starts receiving RTP packets. At 
this stage, if the device receives additional 18x responses, it 
does not resume playing the local ringback tone. Note that