User Manual

Circuit switched services
99-137719-D Confidential - For internal use 7-9
7777
Data interfaces
7.5.4.2 Emergency calls
For emergency calls (defined by emergency destination numbers such as 112 or 911
configured in the BGAN XL Radio Module and on the USIM) the header field Priority is
used (RFC3261 [5]). To setup a mobile originated emergency call the following header
field must be present:
Priority: emergency
Example: Emergency
INVITE sip:[e-mail] SIP/2.0
…
To: 112 <sip:[e-mail]>
Priority: emergency
7.5.5 Network and BGAN XL Radio Module cause codes
The BGAN XL Radio Module supports the header field Reason (RFC 3326 [6]) for
detailed network and RM cause code signalling to the SIP peer. The header field
Reason contains a protocol, a protocol cause and a reason text. The protocols used by
the RM are Q.850 for network cause codes and a proprietary X-BGAN protocol defined
for RM status cause codes.
Example: Cause codes
Reason: Q.850 ;cause=19 ;text="User alerting,
no answer"
Reason: X-BGAN ;cause=105 ;text="No satellite signal"
The SIP peer may include a Q.850 reason cause when rejecting an MT call or
terminating an established call. This cause will then be relayed to the BGAN network.
It is recommended to log the RM status cause codes for diagnostic purposes.
7.5.6 Supplementary services
7.5.6.1 Call Hold/Retrieve
If the SIP peer wishes to place an on-air call on hold it must send a re-invite having the
SDP session attribute a=sendonly. To retrieve the call it must send a re-invite having
the SDP session attribute a=sendrecv.
7.5.6.2 Multiple simultaneous on-air calls
The RM supports two simultaneous on-air calls of which one must be placed on hold.
I.e. to dial a second on-air call the SIP peer must place the first call on hold before
sending the invite for the second call. When the second call is established it is possible
to toggle between the two calls by placing the active call on hold and then retrieving
the other call.