Android SMS Gateway Scenario 1756: Edtech multi-device failover in practice

Summary

Scenario 1756 is exam-clash at 08:25: two papers same morning, room-move SMS, spare radio already paired, PTA CSV held until DLR drains. Service pricing is based on device count and total SMS sent through the gateway. You need a working Android phone with a SIM and SMS credit from your mobile operator. Operator message costs are yours—we do not sell carrier SMS balance.

If candidates sit in the old hall and the spare is in IT, you did not fail over. You ran a desk drill.

Not a CodeCanyon “school SMS” pack. Device meters apply — Twilio vs Android SMS gateway.

Key takeaways

• Scenario 1756 is 08:25 exam-clash room-move failover — not exam-window, homework, enrollment, snow-day, PTC OTP, results, late-bus, field-trip, after-school, lunch till, away-fixture, inset, sports-rain, seating, swim, minibus, assembly, uniform shop, canteen till, music cancel, library overdue, PE kit, choir pickup, detention, parents-evening 16:50, nursery collection 16:05, year-photo 08:40, after-exam pickup 15:55, or instrument-hire 08:05.
• A spare that IT racks at 07:40 and unplugs at 08:00 is not clash-morning HA.
• Priced by devices and SMS send volume. You use your own phone and operator SMS credit. Free is 300 SMS lifetime, 1 device. Developer is 25,000 SMS per year.
• Starter is 2 devices; the spare still counts.
• Hold PTA lists until the last room-move notice drains.
• Canary both radios at 08:05, not at the overnight MIS check.

Related reading

education SMS, multi-device SMS gateway, how an Android SMS gateway works, GOV.UK instructions for conducting examinations.

Context

Clash list lands at 08:10. Candidates still walk to hall A unless SMS lands. PTA still wants a raffle CSV.

Free (300 SMS lifetime) is a rehearsal year. Developer is 25,000 SMS per year.

Core scenario guidance

08:25 is clash room-move, not seating swap 07:35. Timezone is the school site, not the MAT office.

Exam-clash failover roles

Cost and ownership

Priced by devices and SMS send volume. You use your own phone and operator SMS credit. The clash spare is a billed device. Duplicate room-move SMS burns airtime.

Name a 07:50–09:30 on-call for clash mornings, not only afternoon MIS.

Operations

08:05 canary both radios. Abort: hold PTA, keep staff OTP, skip a second “all candidates” blast. Do not “resend clash.”

Security and compliance

Short bodies. No candidate numbers plus names in one SMS. Authenticate MIS hooks. PTA lists are promotional.

Decision guide

Ship when 08:05 canary is green and the spare stays powered through 08:50. Delay if radios lock in a cupboard after 17:00. If handsets are forbidden, CPaaS for staff OTP.

Checklist

• Both SIMs paired overnight.
• 08:05 dual canary.
• Spare live before 08:25.
• Staff OTP isolated.
• PTA held.
• Airtime before 07:50.
• Battery exemptions.
• School locale.
• Clash-morning on-call named.
• Device cap includes spare.

Next steps

Review device and SMS volume pricing, device setup, SMS API documentation.

Deep dive: production hardening

A cleaner unplugging USB at 07:55 is an outage at the hall. Watch DLR on both radios, not MIS 200s.

Deep dive: scaling and failure modes

Multi-site exam weeks add devices before inventing a hidden unlimited-handset SKU. Raise OEM ceilings; fair-use remains.

Deep dive: integration discipline

Idempotency on site_id + clash_id + kind (move|ping). MCP is a REST wrapper — live fields in Developer Center.

Priced by devices and SMS send volume. You use your own phone and operator SMS credit.

08:05 clash drill

Canary both radios. Kill primary. Confirm spare sends the room-move. Hold PTA during the wave.