What are the differences between AOBRD and ELD?

The differences between AOBRD and ELD have mostly to do with technical specifications outlined in each Code of Federal Regulation (CFR) by the Federal Motor Carrier Safety Administration (FMCSA). In general, the requirements for ELD are more stringent. See the comparison chart below.
Feature / Function
1988 AOBRD Rule
2015 ELD FInal Rule
Integral Synchronization
Integral synchronization required, but term not defined in the FMCSRs.
Integral synchronization interfacing with the CMV engine ECM to automatically capture engine power status, vehicle motion status, miles driven, engine hours.

*(CMVs older than model year 2000 exempted)
Recording Location Information
Required at each change-of-duty status. Manual or automated.
Require automated entry at each change-of-duty status at 60-minute intervals while CMV is in motion, at engine-on and engine-off instances, and at beginning and end of personal use and yard moves.
Graph Grid Display
Not required - "time and sequence of duty status changes."
ELD must be able to present a graph grid of driver's daily duty status changes either on a display or on a printout.
HOS Driver Advisory Messages
Not addressed.
HOS limits notification NOT required.

"Unassigned driving time/miles" warning provided upon login.
Device "Default" Duty Status
Not addressed.
On-duty not driving, when CMV has not been in motion for 5 consecutive minutes, and driver has not responded to an ELD prompt within 1 minute.

No other nondriver-initiated status change is allowed.
Clock-time Drift
Not addressed.
ELD time must be synchronized to UTC, and absolute deviation must not exceed 10 minutes at any point in time.
Communications Methods
Not addressed - focused on interface between AOBRD support systems and printers.
1. Telematics: At minimum, ELD must transfer data via both wireless Web services AND wireless email.

2. Local Transfer: At minimum, the ELD must transfer data via both USB 2.0 AND Bluetooth.

Both types of ELDs must be capable of displaying a standardized ELD data set to authorized safety officials via display or printout.
Resistance to Tampering
AOBRD and support systems must be, to the maximum extent practical, tamperproof.
ELD must not permit alteration or erasure of the original information collected concerning the driver’s ELD records or alteration of the source data streams used to provide that information.

ELD must support data integrity check functions.
Identification of Sensor Failures and Edited Data
Must identify sensor failures and edited data.
ELD must have the capability to monitor its compliance (engine connectivity, timing, positioning, etc.) for detectable malfunctions and data inconsistencies.

ELD must record these occurrences.