Selective Signaling "SS-1" is a 2 and/or 3 digit dial system used by the Federal Aviation Administration "FAA" within their National Airspace System "NAS" Ground-to-Ground Air Traffic Control Network. It is used on leased and FAA lines between the Air Route Traffic Control Center's "ARTCC", Terminal Radar Approach Control "TRACON", Air Traffic Control Tower's "ATCT", Lockheed Martin Flight Service Hub's "FS-21", Military, National Weather Service and nongovernmental aviation facilities for the control and management of aircraft flights.

The GL's SS1 Analyzer detects and analyzes tone sequences that make up SS1 dial digits. Sequences of pulse and guard tones are detected, decoded, and assembled into their corresponding dial digits. The tone sequences are also verified for compliance against a "specification" parameter file which can correspond to published standards or user criteria.

The SS1 Emulator (Dialer) application provides the ability to setup and dial tone sequences that make up SS1 dial digits. The applications' interface includes options to setup Dial Code, and control Mask (pulse) & Space (guard) frequencies and duration, Initial, Nominal, and Final Durations, Timeout definitions, Transmit Channel, and other similar parameters related to the dial code.

• Real-time and File-based) analysis
• Generate and introduce SS1 Dial Codes on Transmit Channels using SS1 Dialer
• Control mark & space frequencies and duration, and power during transmission of SS1 Tones
• Dual monitoring capability allowing multiple instances of SS1 analyzer to simultaneously tap E and W direction traffic.
• Ability to capture either TDM or audio signals
• Configuration screens to conveniently specify the criteria used to evaluate the sequence of SS1 tones, including specifying the use of 2-digit or 3-digit dial codes. See the figure below.
• Display of received dial codes, including the characteristics of the underlying tones. Dial codes whose underlying tone sequences do not meet stated criteria are clearly identified with the erroneous tone characteristics highlighted
• Provides controls to save sets of evaluation criteria, to reinstate previously saved criteria, and to reinstate factory default (industry standard) settings
• Save results to files in a form that is widely understood by popular desktop data management and analysis tools such as Microsoft® Access and Microsoft® Excel
• Allows easy reviewing any number of selected dial code sequences and their underlying tone sequences while ongoing capture and analysis is proceeding
• Operate the SS1 Analyzer either remotely from the data acquisition site, or as on the same PC that is capturing the data
• Examine a faulty dial code at length with Review Dial Code and Spectral Graph features, even as a run is in progress.