Key Takeaways
- Paving dual-SIM is plant vs train: slot A for plant holds, slot B for paver-train ETAs.
- Truck last-four in SMS is enough. Do not put plant-gate PINs or mix tickets in the same body.
- Keep dispatcher OTP off the tablet that dumps plant-hold 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 plant holds onto the paver corridor.
Summary
Logistics dual-SIM in scenario 1539 is asphalt paving: plant holds on slot A, paver-train ETAs on slot B. Unlike depot ETA, last-mile, returns, cold-chain, air-cargo, port-gate, rail, customs, DG/hazmat, pick-wave, PUDO, barge, mine-haul, hospital STAT, ferry RoRo, jobsite crane, municipal waste, snow-plow salt-bay, grain-elevator dump, lumber kiln, pipeline ROW, quarry blast, wind-farm CTV, logging landing, or ready-mix pour, this split is an asphalt plant versus the paving train, not a concrete slab.
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.
A mix ticket in SMS is a spec you leaked. Route plant holds on slot A. Send truck last-four. Keep the PIN in dispatch.
Key takeaways
- Paving dual-SIM is plant vs train: slot A for plant holds, slot B for paver-train ETAs.
- Truck last-four in SMS is enough. Do not put plant-gate PINs or mix tickets in the same body.
- Keep dispatcher OTP off the tablet that dumps plant-hold 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 plant holds onto the paver corridor.
Related reading
Start from multi-device and dual-SIM routing, compare device and SMS volume pricing, open device setup, and review FHWA paving notes where they apply.
Context
Plant desks land here after a reboot swapped slots and a plant hold went out on the paver SIM, or after a gate PIN leaked in an ETA. Dispatcher OTP cannot share that tablet.
Core scenario guidance
Map slot A to plant holds, slot B to paver ETAs. Template: truck last-four. PIN in dispatch. Re-pair after reboot. Isolate OTP.
| Lane | SMS body | Fail closed |
|---|---|---|
| Slot A plant | Hold + last-four | Mix ticket |
| Slot B paver | ETA window | Gate PIN |
| Reboot | Re-map slots | Assume order held |
| Dispatcher OTP | Separate device | Same SIM as plant burst |
Canary a staff hold after OS updates. MCP wraps REST. Developer Center owns fields.
Cost and ownership
Devices + volume + operator airtime on every retry. Developer is 25,000 SMS per year. Free (1 / 300 / 300) proves pairing, not a plant desk.
Operations
Daily last-seen, battery, slot map, duplicate load ids. After SIM reseat, one staff hold. On-call before unattended night paving.
Security and compliance
Plant holds reveal paving timing. Encrypt at rest. Never log gate PINs. Verify TLS on every callback.
Decision guide
Ship when slot maps, last-four templates, and OTP isolation exist. Delay if a reboot can swap plant onto paver. If zero phone ops is mandatory, evaluate CPaaS for that slice.
Checklist
- Slot A plant / slot B paver.
- No PIN in SMS.
- Re-map after reboot.
- OTP isolated.
- Spare paired.
Next steps
Return to Open source guide, compare device and SMS volume pricing, open device setup, and confirm APIs in SMS API documentation.
Deep dive: production hardening
Slot remaps after reboot are non-negotiable. Dual-SIM plant tablets fail when OEM killers sleep the plant slot. Battery exemptions dominate overnight paving.
Deep dive: scaling and failure modes
Scale is loads times holds, not a blast of the crew file. Never claim unlimited free cloud SMS credits with no device or volume meter.
Deep dive: integration discipline
Developer Center owns live API parameters. Persist load id. 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
