Submitting messages with SMPP.
Messages should be submitted with submit_sm using short messages fields. This packet contains the sender and recipient address, message body, and some other optional parameters.
If the message is passed to the Carrier Partner for delivery, the response to the submit_sm - submit_sm_resp - will contain error 0.
If the submit_sm_resp is not positive, it will contain an error indicating the message was rejected.
For more information on SMPP errors, see this list.