How quickly are handset or SMSC acknowledgements delivered?
Short Message Service Center (SMSC) acknowledgements are typically returned almost instantly to the SAP Digital Interconnect's Hub but may not be processed instantly. Instead, it may take 5 to 10 seconds for our system to process and deliver the SMS acknowledgement.
The timing of the return of handset acknowledgements depends upon the transit times through the operator systems. This can take up to 24 hours in certain situations. Upon receipt into the SAP Digital Interconnect system, the acknowledgements are typically processed and delivered within 10-20 seconds.
Bhavesh Mistry Quality Of Service – SAP Digital Interconnect SAP (UK) Limited