Two common ELD hardware designs
An electronic logging device (ELD) has to be synchronized with the vehicle engine so it can record engine power status, vehicle motion, distance and engine hours. How that data reaches the driver and the cloud is where designs differ.
| Question | Bluetooth ELD (dongle + phone app) | Non-Bluetooth ELD (own modem / display) |
|---|---|---|
| How it connects to the truck | Plugs into the diagnostic port (OBD-II, 6-pin or 9-pin) | Plugs in or is hardwired to the vehicle |
| Link to the driver | Bluetooth to a phone or tablet running the ELD app | Wired or dedicated in-cab display or tablet |
| Link to the cloud | Usually the phone's mobile data or Wi-Fi | Usually a built-in cellular modem |
| Hardware cost | Lower, the driver's phone is the screen | Higher, more parts in the device |
| Main dependency | Phone battery, pairing and app stability | Cellular coverage and device installation |
Bluetooth ELD: where it works well
A Bluetooth dongle keeps the hardware small and cheap, installs in minutes without tools, and lets the driver use a phone they already carry. Bluetooth Low Energy (BLE) is the usual choice because iPhones generally only allow BLE links to third-party accessories, so a BLE device is easier to support on both Android and iOS.
The trade-offs are practical. If the phone dies, loses its app permissions or drops the pairing, the driver's screen stops. The device must also store events while the phone is out of range and sync them later without gaps or duplicates. That offline handling is firmware work, and it is where cheap designs fail.
Non-Bluetooth ELD: where it works well
A device with its own cellular modem keeps sending data to the cloud even if the driver's phone is off. A wired or dedicated display removes pairing problems and gives fleet managers a unit they control. The cost is higher hardware, a SIM plan, and sometimes professional installation.
What the FMCSA specification says about Bluetooth
The ELD rule (49 CFR Part 395, Subpart B, with the technical specification in Appendix A) does not require Bluetooth between the device and the driver's phone. Bluetooth appears in the specification as one option for local transfer of the output file to a safety official at roadside, alongside USB 2.0. The telematics options are wireless web services and email. A provider chooses which transfer methods it supports and describes them when it registers the ELD.
Bluetooth is a design choice, not a compliance feature. Using a Bluetooth dongle, or avoiding one, does not make an ELD FMCSA compliant. Compliance depends on the complete system: firmware, the ELD app, HOS logic, data recording, malfunction and diagnostic handling, data transfer and the provider's registration. Always read the current rule text.
How to choose
- Owner-operators and small fleets on a budget: a Bluetooth dongle with a good phone app is usually enough, provided drivers keep a charged, supported phone in the cab.
- Fleets that want control over the screen and data path: a unit with its own modem and display costs more but removes the dependency on personal phones.
- ELD software providers: decide early which hardware you will support. Protocol coverage (J1939, J1708/J1587, OBD-II), SDK quality, offline storage and GPS accuracy matter more than the Bluetooth label.
How Inurum approaches ELD hardware
Inurum builds ELD software for partners and has integrated a third-party BLE interface, the PT-30, into its ELD. For a deeper look at that class of device, read the PT-30 technical overview. If you are planning an ELD product, see our white-label ELD software page. Hardware certification and ELD registration stay with the partner.
Frequently asked questions
What is a Bluetooth ELD device?
A Bluetooth ELD device is a unit plugged into the truck's diagnostic port that reads engine data and GPS and sends it over Bluetooth to a driver's phone or tablet. The app on that phone or tablet shows the logs and normally sends data to the cloud over the phone's mobile connection.
What is a non-Bluetooth ELD?
It is an ELD that does not rely on a Bluetooth link to a driver's phone. Typically the hardware has its own cellular modem and either a wired in-cab display or a dedicated tablet. The design choice affects cost, installation and what happens when a phone is lost or switched off.
Does the FMCSA require Bluetooth in an ELD?
No rule says an ELD must use Bluetooth to reach the driver's phone. The FMCSA technical specification lists Bluetooth and USB 2.0 among the options for local data transfer to an inspector, and web services and email for telematics transfer. Check the current text of 49 CFR Part 395 Subpart B and its Appendix A for the exact requirement.
Which is cheaper, a Bluetooth or a non-Bluetooth ELD?
Bluetooth dongles are usually the cheaper hardware because the driver's own phone provides the screen and the data connection. Total cost still depends on app subscriptions, installation, support and device replacement, so compare the full cost over several years.
Does Inurum work with Bluetooth ELD hardware?
Yes. Inurum has integrated a third-party Bluetooth Low Energy ELD interface, the PT-30, into its ELD software, and builds ELD software and hardware for partners. This is not a claim that any complete solution is FMCSA certified or registered; the registering partner handles that.
Planning an ELD product for the US market?
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