Key Takeaways
- Scenario 850 is field-survey USSD for enumerators (*88# trees), not voucher PIN confirm or *123# balance.
- A timeout mid-questionnaire is a resume problem, not a “household refused.”
- Community alert SMS and donor appeals never share the enumerator modem.
- Answers can be personal. Menus and logs need the same care as a paper form.
- Priced by devices and SMS send volume. You use your own phone and operator SMS credit. Free: 1 device, 300 SMS lifetime, 300 contacts. Developer: 25,000 SMS per year.
Android SMS gateway scenario 850 is a household survey where enumerators walk a USSD tree because data coverage is poor. The Android gateway automates test trees and HQ monitors — it does not replace consent at the door. Timeouts mid-form are normal.
Priced by devices and SMS send volume. You use your own phone and operator SMS credit. USSD · Developer Center. GSMA.
Q3 timeout — resume, do not close case
Enumerator menu, not a blast
Document the tree: language, skip logic, last-question resume. HQ can run canary sessions on a monitor modem. Live interviews stay on field handsets unless you have an explicit centralization design.
If a timeout marks the household “refused,” your dataset is a map of radio quality, not of answers.
Survey USSD vs community SMS
| Work | Radio | Device | Consent |
|---|---|---|---|
| Survey tree | USSD | Enumerator / monitor | Door + programme |
| Cluster ops SMS | SMS | Ops pool | Staff |
| Community / donor SMS | SMS | Other MSISDN | STOP |
Device caps: 2 / 5 / 15.
Partial trees
Store session id and last node. Do not restart at Q1 after a drop — enumerators will skip or fabricate. Dual SIM.
Timeout ≠ missing household
QA flags radio timeouts separately from refusals. Cap USSD retries. REST samples: PHP, C#. MCP wraps REST.
Devices and prepaid
Priced by devices and SMS send volume. You use your own phone and operator SMS credit. Free: 300 lifetime. Developer: 25,000 SMS per year. We do not sell field airtime. Pricing.
Cluster week
Name who tops up enumerator SIMs. Canary *88# after carrier promo weeks. Setup · STOP on community lanes.
Respondent data
Menu answers can identify households. Restrict who can pull sessions. No public Slack screenshots.
ODK on data instead
If 3G is good enough, a data form beats USSD. Keep USSD when the menu is the only reliable path.
Checklist
- Resume node persisted.
- Timeout ≠ refusal in QA.
- Survey modem ≠ donor SIM.
- Codes documented per MNO.
- Prepaid owner per cluster.
- Canary after menu changes.
Next steps
Run a three-question canary, drop the session at Q2, prove resume. Downloads · Docs.
Related product pages
Jump to the live product docs for this topic—not another long-form article.
- USSD balance and menu automationOperator USSD codes
- SMS API documentationLive endpoint reference
- device and SMS volume pricingPlans and allowances
- Android SMS gateway product guideDefinition, product, and how to buy
