Key Takeaways
- DG dual-SIM is yard vs public corridor: slot A for hazmat holds, slot B for public-road ETAs.
- UN number class in SMS is enough. Do not put SDS links or access codes in the same body.
- Keep broker OTP off the tablet that dumps DG cut-off notices.
- Service pricing is devices plus SMS send volume. You bring the Android phone and operator credit.
- Free is 1 device, 300 SMS lifetime, 300 contacts. Developer is 25,000 SMS per year.
- Re-map slots after every reboot. A swapped SIM sends yard holds onto the public corridor plan.
Summary
Logistics dual-SIM in scenario 519 is dangerous-goods routing: yard holds, placard checks, and public-road ETAs. Unlike depot city ETAs, last-mile corridors, reverse logistics, cold-chain, air-cargo, ocean gate, rail ramps, or customs crossings, this map is UN class and segregation.
Service pricing is devices plus SMS send volume. You bring the Android phone and operator SMS credit. Free is 1 device, 300 SMS lifetime, 300 contacts. Developer is 25,000 SMS per year. Starter, Professional, and Business list Unlimited SMS as platform send volume; devices and airtime stay metered.
An SDS link in the same SMS as a UN number is a document you leaked to a stolen phone. Route the hold. Keep the sheet in the portal.
Key takeaways
- DG dual-SIM is yard vs public corridor: slot A for hazmat holds, slot B for public-road ETAs.
- UN number class in SMS is enough. Do not put SDS links or access codes in the same body.
- Keep broker OTP off the tablet that dumps DG cut-off notices.
- Service pricing is devices plus SMS send volume. You bring the Android phone and operator credit.
- Free is 1 device, 300 SMS lifetime, 300 contacts. Developer is 25,000 SMS per year.
- Re-map slots after every reboot. A swapped SIM sends yard holds onto the public corridor plan.
Related reading
Start from multi-device and dual SIM routing, pair in the device setup guide, confirm fields in SMS API documentation, and review UNECE dangerous-goods notes.
Context
Yard desks land here after a reboot swapped slots and public-road drivers got a DG-hold template with an SDS leftover from a test. Facility OTP cannot share that burst.
Core scenario guidance
Pin slot A to yard DG events and slot B to public ETAs. Re-pair after reboot. Never put SDS or gate codes in SMS. Isolate OTP. Cap retries per UN event.
| Event | Slot | Fail closed |
|---|---|---|
| Yard / placard hold | A · DG plan | Public SIM after reboot |
| Public ETA | B · corridor plan | Same body as SDS link |
| Gate code | Portal only | SMS + UN number |
| Facility OTP | Separate device | Same tablet as cut-off |
Canary both slots after OS updates. MCP wraps REST. Developer Center owns fields.
Cost and ownership
Two SIMs still count as one device if they share a handset — plus volume plus two airtime bills. Developer is 25,000 SMS per year. Free (1 / 300 / 300) proves pairing, not a yard.
Operations
Daily last-seen, battery, slot map, DLR by corridor. After SIM reseat, one staff hold and one public ETA. On-call before unattended cut-off nights.
Security and compliance
DG events reveal cargo class. Encrypt at rest. Rotate keys. Never log SDS URLs in Slack. Verify webhooks if a TOS fires the SMS.
Decision guide
Ship when slot map, SDS isolation, and spare exist. Delay if reboot remap is untested. If zero phone ops is mandatory, evaluate CPaaS for that slice.
Checklist
- Slot A/B documented.
- No SDS in SMS.
- OTP isolated.
- Reboot remap drill.
- Spare paired.
Next steps
Return to Android SMS gateway API, compare device and SMS volume pricing, open device setup, and confirm APIs in SMS API documentation.
Deep dive: production hardening
Dual-SIM routing fails when slot maps drift after reboot. Battery exemptions dominate overnight yards. OEM killers look like TOS outages.
Deep dive: scaling and failure modes
Scale is UN events, not one blast to every driver. Never claim unlimited free cloud SMS credits with no device or volume meter.
Deep dive: integration discipline
Developer Center owns live API parameters. Persist UN event id and slot. MCP is a REST wrapper. If zero phone ops is mandatory, evaluate CPaaS. You bring the Android phone and operator credit.
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
- transactional SMS for orders and alertsEvent-driven messages
- SMS delivery reports (DLR)Delivery status tracking
- SMS API documentationLive endpoint reference
