ZXMSG 5200 (V2.0) Technical Manual 
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ServiceChange (TerminationID, 
ServiceChangeDescriptor 
)  
Parameters 
The  H.248  command  contains  different  Descriptors  that  work  with 
commands  to  transfer  media  control  information  between  MGC  and  MG. 
These descriptors include:  
1.  Modem Descriptor 
Define modem type and parameter. 
2.  Multiplex Descriptor 
Multiple media streams are carried on different carriers in a multimedia 
call, . The Multiplex Descriptor associates media with carrier. 
3.  Media Descriptor 
Define all media streams parameters. 
4.  Termination State Descriptor 
Define properties of the terminations that are unrelated with streams.  
5.  Stream Descriptor 
List  the  remote/local/localControl  descriptors  of  an  individual  media 
stream. 
6.  LocalControl Descriptor 
Define some media stream related characteristics in a termination. 
7.  Local and Remote Descriptor 
Local  means  media  streams  that  are  received  by  MG,  and  Remote 
means  media  streams  that  are  sent  by  MG.  MG  uses  the  Local  and 
Remote  descriptors  to  reserve  and  use  MG  resources,  for  media 
encoding for specified streams and their used terminations. 
8.  Events Descriptor 
Contain a list of a series of events that MG needs to detect and report.  
9.  EventBuffer Descriptor 
Contain  a  series  of  parameter  events  for  termination’s  detection  and 
buffer. 
10. Signals Descriptor 
Identify signal tones that MGC requests one termination on MG to play. 
11. Audit Descriptor 
Define  which  information  should  be  audited,  and  define  a  list  of 
descriptors to be returned. 
12. ServiceChange Descriptor 
Contain  such  parameters  as  service  change  mode,  service  change 
reason and time stamp.