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ELD Technical Specifications

NOTE: This guidance was rescinded on March 10, 2022, and is no longer in effect.  Please see revised guidance FMCSA-ELD-Technical-Specifications-FAQs(2022-03-10).




Q1. Why are technical specifications in the Electronic Logging Device (ELD) rule?

. The technical specifications in the ELD rule ensure that manufactures develop compliant devices and systems for uniform enforcement of hours of service.

Q2. Will FMCSA provide the eRODS application for vendors to test against?

. No, FMCSA will not provide the RODS application for vendors to test against. Compliance test procedures are available on the ELD website to allow vendors to test their devices’ compliance with the ELD rule technical specifications.

Q3. Is a physical connection between the ECM and ELD required in order to establish integral synchronization with the engine?

No. The ECM and ELD may be connected by serial or Control Area Network communication protocols. Hard wiring to the J1939 plug and Bluetooth connectivity are examples of methods of receiving the data from the ECM or vehicle data bus.

Q4. If an ELD loses connection to the ECM how will the device report a system failure?

. An ELD must use onboard sensors and data record history to identify instances when it may not have complied with the power requirements specified in the ELD rule.

Q5. Must the manufacturer self-certify and register every version or firmware update to the ELD?

The manufacture must register each model and version and self-certify that each particular ELD is compliant with the ELD rule. The manufacturer must decide whether a firmware update is sufficiently
significant to change the registration information. FMCSA did not specify parameters for version revisions.

Q6. Are vendors required to update or register each different configuration of hardware, even though the product is the same as an application (APP) (e.g., black box and Samsung, black box and iPhone, black box and Nexus)?

. Vendors should register each device bundle if they have different operating systems (e.g., an iOS-based bundle and an Android-based bundle would be considered two registered devices).

Q7. Does the registration process require companies to exclusively use FMCSA’s test procedure? Will vendors have access to testing facilities for ELDs?

No. ELD manufacturers may use any test procedure they choose and note this in the registration. FMCSA will not provide a third-party testing service. FMCSA will only investigate devices that are suspected of not conforming to specifications, and will conduct testing with the FMCSA compliance test procedure during its investigation.

Q8. How will CMV environmental specifics be tested with the ELD – for example, mounting and connections to the ECM?

FMCSA does not specify testing requirements for connectivity with the vehicle. Each ELD provider is responsible for connectivity testing.

Q9. How will the ELD report on-duty not-driving status when the origin of the duty status is automatic instead of driver-input?

The ELD will report on-duty not-driving status based on automatic detection, starting from the time the vehicle is no longer in motion.

Q10. The Event Checksum Calculation describes the individual items to be included in the calculation. Number 9 says “CMV Number.” Is this the CMV VIN or the CMV Power Unit Number?

. FMCSA showed a CMV number, as an example, in the header output file. The intent was to allow an additional vehicle identification number if an operator had numbered vehicles and chose to add company- assigned numbers to the CMV header data.
Q11. Are unassigned driving reports required to be available at roadside?

Yes. Section, requires the inspected driver’s profile and the unidentified driver profile to be available as separate reports at roadside either by printout or display. If there are no unidentified driver records existing on the ELD for the current 24-hour period or for any of the previous 7 consecutive days, an ELD does not need to print or display unidentified driver records for the authorized safety official. Otherwise, both reports must be printed or displayed and provided to the authorized safety official.

Q12. How should the ELD handle the dashboard odometer display not matching the odometer value returned by the Engine Control Module (ECM)?

. For instance, when the engine is replaced and the value is not synchronized.The ELD is required to obtain and display the ECM value at all times. Safety officials will use the odometer value reported on the ELD. Note that documentation of engine changes is required by 49 CFR Part 379 Appendix A to be maintained at the carrier’s place of business.


Regulatory Topic: ELD Guidance
Last updated: Monday, April 9, 2018