Delivery Notifications are message acknowledgments. When delivering messages through the Digital Interconnect network, customers can request to receive the following types of message acknowledgment: Digital Interconnect Ack, SMS-C Ack, Handset Ack. For unsuccessful delivery attempts, a negative acknowledgment (Nack) is returned outlining the reason for failure.
Note: Delivery notifications are an operator-dependent feature, and that not all operators support handset acknowledgments.
When sending an SMS, most mobile operators will return a notification called a delivery receipt to let the sender know whether or not the message was delivered to the handset. Some Short Message Service Centers (SMSCs) will return a delivery receipt when a message has been accepted or if the message is buffered in the SMSC, for example if the handset is switched off, although not ideal this is sometimes unavoidable due to operator's restrictions.
If an SMS is not delivered (even after the SMSC retry cycle is complete) then a delivery receipt, with an error code indicating why the message failed will be sent. A complete list of delivery receipt error codes can be found in our Developer documentation.
The destination operator is the operator to which the subscriber’s handset is attached. In most cases the destination operator is the home network but when a subscriber is roaming, then the destination operator will be the network on which the subscriber is roaming.
Direct Inward Dialling (DID) is a service provided by a local phone company (or local exchange carrier) that provides a block of telephone numbers for calling into a company’s private branch exchange (PBX) system. Using DID, companies can offer customers individual phone numbers for each person or workstation within the company without requiring a physical line into the PBX for each connection.