Key Takeaways
- Scenario 112 is greenhouse 07:15 frost-cancel failover — not DT 08:55, ICT 08:45, science-lab 08:35, packed-lunch 07:30, or year-photo 08:40.
- A 07:15 that stays on a single SIM when the site radio dies is pupils still walking to the polytunnel, not a tidy MIS log.
- 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 horticulture spare still counts.
- Hold PTA CSV until greenhouse DLR drains.
- Canary the horticulture SIM at 06:55, not at last night’s portal job.
Summary
Scenario 112 is a greenhouse frost cancel: 07:15 parent SMS with a live spare if the site radio dies, 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 frost hits at 07:08 and the spare is still in a locked potting shed, you logged a weather note. You did not stop the walk to the polytunnel.
Not a CodeCanyon “school SMS” pack. Device meters apply — Twilio vs Android SMS gateway.
Key takeaways
- Scenario 112 is greenhouse 07:15 frost-cancel failover — not DT 08:55, ICT 08:45, science-lab 08:35, packed-lunch 07:30, or year-photo 08:40.
- A 07:15 that stays on a single SIM when the site radio dies is pupils still walking to the polytunnel, not a tidy MIS log.
- 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 horticulture spare still counts.
- Hold PTA CSV until greenhouse DLR drains.
- Canary the horticulture SIM at 06:55, not at last night’s portal job.
Related reading
multi-device and dual SIM routing, how an Android SMS gateway works, device setup, DfE health and safety advice for schools.
Context
Grounds staff flags frost at 07:08. Period 1 starts at 08:45. PTA still wants a raffle CSV.
Free (300 SMS lifetime) is a rehearsal year-group. Developer is 25,000 SMS per year.
Core scenario guidance
07:15 is greenhouse HA, not DT isolate 08:55 or lab cancel 08:35. Timezone is the school, not the trust HQ.
Greenhouse failover roles
| Role | When | Typical fail |
|---|---|---|
| 07:15 frost-cancel SMS | School local, before P1 | Primary SIM asleep; spare in a locked potting shed |
| Duplicate cancel | Same set_id same morning | Second 07:15 treated as a new blast |
| Staff OTP | Transactional, own pool | Dumped onto the horticulture radio |
| PTA / raffle | Held until last cancel DLR | Released at 07:00 into greenhouse SMS |
Cost and ownership
Priced by devices and SMS send volume. You use your own phone and operator SMS credit. The horticulture spare is a billed device. Failover retries burn airtime.
Name a 06:40–09:00 on-call for greenhouse mornings, not only weekday MIS.
Operations
06:55 canary. Abort: hold PTA, keep staff OTP, skip a second “all parents” blast. Do not “resend the year.”
Security and compliance
Short cancel texts. No pupil names in SMS. Authenticate MIS hooks. PTA lists are promotional.
Decision guide
Ship when 06:55 canary is green and the spare is powered in the office, not the potting shed. Delay if both radios share one USB. If handsets are forbidden, CPaaS for staff OTP.
Checklist
- Horticulture SIM paired before 06:40.
- 06:55 canary.
- Spare live in the office.
- Staff OTP isolated.
- PTA held.
- Airtime before 06:40.
- Battery exemptions.
- School locale.
- Greenhouse 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 locked shed at 07:08 is an outage at 07:15. Watch DLR, not MIS 200s.
Deep dive: scaling and failure modes
Two-site horticulture mornings add devices before inventing a hidden unlimited-handset SKU. Raise OEM ceilings; fair-use remains.
Deep dive: integration discipline
Idempotency on set_id + date + kind (frost|failover). 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.
06:55 greenhouse drill
Canary. Kill the primary. Confirm the spare sends one frost-cancel SMS. Hold PTA during the wave.
Related product pages
Jump to the live product docs for this topic—not another long-form article.
- multi-device and dual SIM routingCapacity and failover
- OTP and 2FA SMS on AndroidAuthentication flows
- SMS delivery reports (DLR)Delivery status tracking
- SMS API documentationLive endpoint reference
