Unstructured Supplementary Service Data (USSD) allows a real-time connection during a session (unlike SMS). The connection is left open on demand, supporting a two-way exchange of data between the device and an application without the need for data connection. SAP IoT Connect 365allows you to maintain either mobile or network-initiated USSD dialogs.
To set up a USS Dialog, you first configure the following on the SAP IoT Connect 365UI:
Ensure the USSD service is enabled by default on the Service Profile, assigned to your endpoints, for which you want to establish an USSD dialog.
Setup an API Callback URL to establish the connection to your server in the Service Profile configuration (this is where any USSD messages sent from the device will be forwarded to by SAP IoT Connect 365's USSD Gateway)
Set the API URL on the "SMS" tab (within the Service Profile configuration) - select "RestAPI" on the drop-down menu for “Interface”
Select the “configuration icon” next to “RestAPI”, input a purpose (name of your choosing) and the URL
(Optional) You can set up a "Secret" to ensure authentication of any USSD requests
Some USSD specs:
Maximum message size is 160 bytes; 182 characters with GSM 7bit encoding, 80 characters with UCS2 encoding
USSD codes in the form of *xxx#
The range 100-109 is preconfigured by default, so your endpoint can address different applications on your server.