It's a diagnostic software that enables comprehensive diagnostics for agricultural and construction equipment, as well as engines manufactured by John Deere. The Electronic Data Link (EDL) is a dealer diagnostic PC-to-vehicle interface compatible with Service ADVISOR software, allowing access to service manuals, technical assistance center (DTAC) data, diagnostics, readings, tests, calibrations, and controller programming. The Service Advisor offers detailed workshop and repair manuals, among other features.