There was a download of ComTekk AvCall 1.0 on the developer's website when we last checked. We cannot confirm if there is a free download of this software available. The software lies within Multimedia Tools, more precisely Editors & Converters. The most popular version of the program 1.0. This program is a product of BW Consultants.
From the developer:
ComTekk AvCall makes use of the computer sound card and software DSP (Digital Signal Processing) techniques to decode and instantly display aviation SELCAL codes, a 2 2 tone signaling system used to "page" aircraft via HF (or VHF) radio on overseas flights.
Simply connect receiver's speaker output to computer's LINE or MIC input.
You may want to check out more software, such as ComTekk Sinad, ComTekk SafAlert or ComTekk iRecall, which might be related to ComTekk AvCall.