This group is the number one resource for everything about the High Frequency Data Link protocol (HFDL aka 'HF ACARS'), which is used to send ACARS-like messages from and to aircraft on shortwave frequencies (2-22 MHz).

HFDL is operated by ARINC as the GLOBALink/HF service, with 15 ground stations spread over the globe. The number of customers is increasing rapidly, with almost 2000 aircraft equipped today!

In this Yahoo group, you'll find:
- HFDL logs from various locations;
- A continuously updated database of all aircraft using HFDL, including their ICAO 24-bit addresses (sometimes referred to as 'Mode S codes');
- WACARS and AirNav data files;
- The latest beta version of PC-HFDL;
- An up-to-date PC-HFDL system table file;
- A set of technical articles about HFDL;
- Answers to many software and hardware questions;
- Plus a lot more!