Short answer
To connect to an SMS provider over SMPP, request a bind and register your source IP addresses, then open a TLS connection to the host and port provided. Send bind_transceiver with your system_id and password, submit messages with submit_sm, acknowledge every deliver_sm receipt, and send enquire_link regularly to keep the session alive.
What the provider gives you
SMPP access is usually provisioned by the provider, not self-served. Tell it your destination countries, sender IDs, expected peak volume and the public IP addresses you will connect from.
| Item | What it is |
|---|---|
| Host and TLS port | Where your client connects |
| system_id and password | Bind credentials; store them as secrets |
| system_type | Usually empty unless the provider sets a value |
| Binds and throughput | How many sessions you may open and the agreed rate per bind |
| IP allow-list | Only registered source IPs can bind |
Open and run the session
A transceiver bind sends and receives on one session. Use separate transmitter and receiver binds only if your client requires them.
- Open a TLS connection to the host and port you were given.
- Send bind_transceiver with system_id and password, and wait for bind_transceiver_resp with command_status 0.
- Submit each message with submit_sm and store the message_id from submit_sm_resp.
- Receive delivery receipts as deliver_sm and answer every one with deliver_sm_resp.
- Send enquire_link while idle and reconnect with backoff if responses stop.
- Close with unbind and wait for unbind_resp.
Which submit_sm fields cause most rejections?
- source_addr_ton and source_addr_npi: 5 and 0 for an alphanumeric sender ID, 1 and 1 for an international number.
- destination_addr: country code plus number, with no plus sign or leading zeros.
- data_coding: 0 for the GSM-7 default alphabet, 8 for UCS-2 (Arabic, emoji and other scripts).
- registered_delivery: 1 to request a delivery receipt.
- short_message holds up to 254 octets; for longer content use the message_payload TLV with sm_length 0, never both.
Common bind and submit errors
OmniChannels.ai provisions SMPP 3.4 binds over TLS per account, with source IPs allow-listed, and resellers and wholesale partners can have dedicated binds.
| command_status | Likely cause | Fix |
|---|---|---|
| ESME_RBINDFAIL | Wrong system_id or IP not allow-listed | Check credentials and source IP |
| ESME_RINVPASWD | Wrong password | Check credentials |
| ESME_RINVSRCADR | Sender ID or its TON/NPI is invalid | Fix the sender and TON/NPI |
| ESME_RTHROTTLED | Sending above the agreed rate | Slow down and retry with backoff |