Known as Ham-Friendly ALE, the amateur radio ALE standard is used to establish radio-communications, through a combination of active ALE on internationally recognized automatic data frequencies, and passive ALE scanning on voice channels and all other channels.

In this technique, active ALE frequencies include pseudo-random periodic polite station identification, while passive ALE frequencies are silently scanned for selective calling.

Automatic Link Establishment, commonly known as ALE, is the worldwide de facto standard for digitally initiating and sustaining HF radio communications.

ALE is a feature in an HF communications radio transceiver system, that enables the radio station to make contact, or initiate a circuit, between itself and another HF radio station or network of stations.

It is programmed with a unique ALE Address, similar to a phone number ( or on newer generations, a username ).

On many ALE radios this is similar to dialing a phone number.

When the distant scanning station detects ALE activity, it stops scanning and stays on that channel until it can confirm whether or not the call is for it.

The two stations ' ALE controllers automatically handshake to confirm that a link of sufficient quality has been established, then notify the operators that the link is up.

With a radio operator initiating a call, the process normally takes a few minutes for the ALE to pick an HF frequency that is optimum for both sides of the communication link.

ALE is most commonly used for hooking up operators for voice contacts on SSB ( single sideband modulation ), HF internet connectivity for email, SMS phone texting or text messaging, real-time chat via HF text, Geo Position Reporting, and file transfer.

The essence of ALE techniques is the use of automatic channel selection, scanning receivers, selective calling, handshaking, and robust burst modems.

This information is coupled with the ALE address of the sending node and the channel the message was received on, and stored in the node's Link Quality Analysis ( LQA ) memory.

When a call is initiated, the LQA lookup table is searched for matches involving the target ALE address and the best historic channel is used to call the target station.

If further digital communication is desired, it may take place via external data modems or via optional modems built into the ALE terminal.

This unusual usage of FEC redundancy is the primary innovation that differentiates ALE from previous selective calling systems which either decoded a call or failed to decode due to noise or interference.

The orderwire message, known as AMD ( Automatic Message Display ), is the most commonly used text transfer method of ALE, and the only universal method that all ALE controllers have in common for displaying text.

By the year 2000, there were enough civilian and government organizations worldwide using ALE that it became a de facto HF interoperability standard for situations where a priori channel and address coordination is possible.

This ability to enable tactical communication in conditions where dedicated trained operators and hardware are inappropriate is often considered to be the true improvement offered by ALE.

ALE is a critical path toward increased interoperability between organizations.

2G ALE SignalThe more common 2G ALE signal waveform is designed to be compatible with standard 3 kHz SSB narrowband voice channel transceivers.

The ALE data is formatted in 24-bit frames, which consist of a 3 bit preamble followed by three ASCII characters, each seven bits long.

Although 3G ALE is more reliable and has significantly enhanced channel-time efficiency, the existence of a large installed base of 2G ALE radio systems and the wide availability of moderately priced ( often military surplus ) equipment, has made 2G the baseline standard for global interoperability.

The 3G ALE modem signal also provides better robustness and can work in channel conditions that are less favorable than 2G ALE.

Each amateur radio ALE station uses the operator's callsign as the address, also known as the ALE Address, in the ALE radio controller.

Apple Lossless, also known as Apple Lossless Audio Codec ( ALAC ), or Apple Lossless Encoder ( ALE ), is an audio codec developed by Apple Inc. for lossless data compression of digital music.

ALE could also refer to:

The common basic world protocol standards for ALE are based on the original US MIL-STD 188-141A and FED-1045, known as 2nd Generation or 2G ALE.

Organizations known to use ALE for Emergency management, disaster relief, ordinary communication or extraordinary situation response include: Red Cross, FEMA, Disaster Medical Assistance Teams, NATO, Federal Bureau of Investigation, United Nations, AT & T, Civil Air Patrol, SHARES, State of California Emergency Management Agency ( CalEMA ), other US States ' Offices of Emergency Services or Emergency Management Agencies, and Amateur Radio Emergency Service ( ARES ).

Non-compact, complete, hyperkähler 4-manifolds which are asymptotic to H / G, where H denotes the quaternions and G is a finite subgroup of Sp ( 1 ), are known as asymptotically locally Euclidean, or ALE, spaces.

The Free Trade Agreement ( FTA ) ( French: Accord de libre-échange ( ALE )) was a trade agreement reached by negotiators for Canada and the United States on October 4, 1987 and signed by the leaders of both countries on January 2, 1988.

A standalone ALE radio combines an HF SSB radio transceiver with an internal microprocessor and MFSK modem.

When not actively in contact with another station, the HF SSB transceiver constantly scans through a list of HF frequencies called channels, listening for any ALE signals transmitted by other radio stations.

To reach a specific station, the caller enters the ALE Address.

The ALE controller selects the best available idle channel for that destination address.

If the callee fails to respond or the handshaking fails, the originating ALE node usually selects another frequency either at random or by making a guess of varying sophistication.

The operator then un-mutes the radio and answers the call then can talk in a regular conversation or negotiates a data link using voice or the ALE built-in short text message format.

The ALE built-in text messaging facility can be used to transfer short text messages as an " orderwire " to allow operators to coordinate external equipment such as phone patches or non-embedded digital links, or for short tactical messages.

One of the new characteristics that embedded microprocessors and computers brought to HF radio via ALE, was alleviation of the need for the radio operator to constantly monitor and change the radio frequency manually to compensate for ionospheric conditions or interference.

For the average user of ALE, after learning how to work the basic functions of the HF transceiver, it became similar to operating a cellular mobile phone.

For more advanced functions and programming of ALE controllers and networks, it became similar to the use of menu-enabled consumer equipment or the optional features typically encountered in software.

An ALE radio system enables connection for voice conversation, alerting, data exchange, texting, instant messaging, email, file transfer, image, geo-position tracking, or telemetry.

In modern HF communications, ALE has largely replaced HF prediction charts, propagation beacons, chirp sounders, propagation prediction software, and traditional radio operator educated guesswork.

High Frequency Internet Protocol or HFIP may be used with ALE for internet access via HF.

An ALE node decodes all received ALE signals heard on the channel ( s ) it monitors.

It utilizes the fact that all ALE messages utilize Forward error correction ( FEC ) redundancy.

By noting how much error-correction occurred in each received and decoded message, an ALE node can detect the " quality " of the path between the sending station and itself.