Selcal is a two-tone 'tag' similar to the alerting system used in fire/EMS
dispatch systems. It is used to help air route controllers keep track of
flights. ACARS is a computer data network on the VHF air band used for
routing flights. There's a similar network on the SW bands called HFDL, not
used as often as ACARS though.

Jeff Seale
Sat800, YB550PE, ETraveller, DX440, BC780, Pro95
Louisville, KY

"Robert11" wrote in message
...
Hello:

Might someone please describe the differences between Selcal and Acars
that
are apparently both
used by commercial aero for air to ground reporting messages ?

Any suggestions for good (free ?) decoders for either ?

Thanks,
Bob