How Many J25 Units Belong in a B2B Pilot?
Size a J25 pilot around the operating decision you need to make—not around a headline distance or an assumed network size. Begin with two equipped endpoints for a direct-link check. Add units only when the test includes more simultaneous roles or one or two participating relay positions. Each equipped participant also needs a compatible paired phone for the workflow being evaluated.
This is a test-layout method, not a universal quantity recommendation. ChatField does not publish a one-size-fits-all pilot size, capacity claim, or coverage guarantee. The buyer should document the route, roles, phone setup, expected communication steps, and acceptance criteria before ordering pilot units.
Start with the decision, then count simultaneous roles
Before choosing a quantity, write the decision that the pilot must support. A procurement team may need to confirm whether two coworkers can exchange local PTT, messages, maps, or position information along a representative no-cell-service route. Another team may need to test whether a participating relay position improves a specific obstructed segment. Those are different questions and require different layouts.
ChatField J25 is a phone-paired LoRa mesh communication terminal. The smartphone remains the operating interface, while the J25 devices provide the local radio and mesh link between equipped teammates. It is not a conventional handheld walkie-talkie, and an unequipped person is not automatically part of the local mesh.
A practical unit-counting matrix
| Pilot question | Minimum active layout | What the count means |
|---|---|---|
| Can two real roles communicate directly on the route? | 2 J25 units and 2 compatible phones | One equipped endpoint for each simultaneous role. |
| Does one participating relay position help on a defined segment? | 3 J25 units and 3 compatible phones | Two endpoints plus one relay participant. |
| Does a two-relay layout help on a defined route? | 4 J25 units and 4 compatible phones | Two endpoints plus two relay participants. |
| Must several moving roles operate at the same time? | 1 active J25 and paired phone per equipped simultaneous role | Count roles that operate concurrently, not every employee on the roster. |
These quantities describe a test arrangement. They do not state a network limit, guarantee that a relay will solve an obstruction, or replace destination-market and workplace requirements. If a buyer wants spares, training units, or shift-change coverage, those should be listed separately rather than hidden inside the test count.
Do not derive quantity from the range figures
The Technology explanation and J25 Specifications provide the bounded product context: ideal open-terrain communication can reach up to 10 km, while ChatField’s urban-obstructed testing is about 5 km. Terrain, buildings, vegetation, interference, antenna position, and carrying method can change the result. Neither figure is a promise that one quantity will cover every route.
Up to two participating J25 nodes may be evaluated as relays. That means a pilot can deliberately compare direct, one-relay, and two-relay results when those layouts match the operating plan. It does not mean every deployment needs two relays or that adding nodes guarantees range.
Pair each unit with a documented phone setup
A unit count is incomplete without a phone-pairing plan. For every active role, record the J25 identifier, phone model, operating-system version, app version, route segment, carrying position, and whether the check is direct or relayed. This keeps a radio result from being confused with a pairing, permission, battery, or app-configuration issue.
Use the same message, PTT, map, and position-update steps at defined checkpoints. Record both successful and failed attempts with time and location. If the local SOS workflow is included, describe it accurately: it alerts equipped teammates and is not public emergency dispatch.
Separate pilot units from procurement volume
The pilot quantity answers, “How many devices are needed to test the representative workflow?” Procurement volume answers, “How many simultaneous roles, training needs, spares, sites, and shifts will the approved operating plan require?” Do not multiply the pilot count into a purchase forecast until the evidence is reviewed.
Before a larger purchase, compare the test record with the available Compliance material, including FCC ID 2BVP9-J25, and confirm the destination-market requirements that apply to the buyer. Equipment authorization evidence should be kept separate from performance results, customer policy, and any claim about emergency services.
A bounded example
Suppose a buyer has two moving crews and one fixed coordination point operating simultaneously. A three-unit direct-role layout can test those three equipped roles. If the same route also requires a dedicated participating relay position, a fourth unit is needed for that separate role. If only two roles operate at once, the buyer should not count inactive roster names as active endpoints.
The example is a planning method, not a recommendation for every customer. The correct count comes from the buyer’s real simultaneous workflow and the test questions that remain unresolved.
Request a pilot-sizing review
Send ChatField a one-page role map, route description, phone list, and the direct-versus-relay questions you need to answer. Contact ChatField to review a bounded pilot layout and request the current evidence set before placing a larger order. ChatField is the brand; Jingxi Box is the company behind the product program; J25 is the current phone-paired terminal, while J28 remains a separate development program.