ALE
From The RadioReference Wiki
Automatic Link Establishment
Provides HF radios the ability to automatically link using the best frequency.
The HF Industry Association has a great page giving an overview of Automatic Link Establishment and how it works. See the following link:
See the ALE Neworks Page for a listing of ALE networks and their frequencies in use
ALE and Amateur Radio
The most current versions of PC-ALE (which see) are available here