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O-CSI and T-CSI difference

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O-CSI and T-CSI difference

Hi all,
I'm reading some documents which is related to HLR, call flow and see that there are flag on HLR: O-CSI and T-CSI but I don't know:
- What is the difference between these two flags?
- What are they used for?
- In which condition are they active ?

Thank you very much.


O-CSI and T-CSI are Camel Data ( SCP address, service key, etc.). These are for originating and terminating calls.

mokhtar zerdo
O-CSI and T-CSI difference

Originating-CSI belong to an IN service for MOC is sent to the VLR together with other mobile subscriber data during location update.
each MOC transaction MSC is triggering IN to get go ahead of routing.
Terminating -TCSI belong to an MTC service is retained in the HLR and is made availible during the interrogation procedure (before MRSN attribution).
TCSI is mostely used for roaming purpuse when MTC call is charged.
once sub in in HPLMN , TCSI is no more useful ( it's suppressed in HLR ).