YYZ by Rush is a pretty obvious example.
YYZ is the IATA airport identification code of Toronto PearsonInternational Airport, near Rush's hometown.
The band was introduced to the rhythm as Alex Lifeson flew them into the airport.
A VHF omnidirectional range system at the airport broadcasts the YYZ identifier code in Morse code.
Peart said in interviews later that the rhythm stuck with them.
Peart and Geddy Lee have both said "It's always a happy day when YYZ appears on our luggage tags.
"The pieces's introduction, played in a time signature of 10/8, repeatedly renders"Y-Y-Z" in Morse Code using various musical arrangements.
"YYZ
" rendered in Morse code:
Y Y Z- . - - - . - - - - . .
Source: Wikipedia
musicfans.stackexchange.com/users/1050/somazo
They've been using talking drums to communicate between African villages for centuries.
( Drum telegraphy )
A village elder, usually the griot , would play the drum to announce weddings, births, deaths, warnings of attack, etc.
The griots of the neighboring villages would then repeat the tune to relay the message to their neighboring villages, so on and so forth.
The drum transcends the villages' individual languages, breaking language barriers and carrying messages very far very quickly.
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In classical music, the term for composition inspired by or including a message or code is a cryptogram.
This approach to composition was sometimes used by the western-European classical composers.
See: en.wikipedia.org/wiki/Musical_cryptogram Bach may have been the most prolific user of cryptograms.
Among his entire compositional output (estimated up to 2000 works) there are dozens of examples where Bach "encoded" his music with secret messages.
Most of them were inside jokes (only meant to amuse himself) and praises to God.
One notable instance is the Bach Motif , which is a sequence of notes that spells out composer Johann Sebastian Bach's last name using note names (using the German names for notes, which include an "H").
It was used frequently by Bach and many of the composers influenced by him.
see
https://en.wikipedia.org/wiki/BACH_motif
Here is a link to the review of an album that purports to feature only famous Bach songs that utilize cryptograms: http://justinpledger.com/2010/12/23/bachs-secret-messages
musicfans.stackexchange.com/users/92/Chris Sunami supports Monica
' Amarok ' by Mike Oldfield is (mostly) instrumental (it contains some shouting and some spoken word.
It also contains a bit of morse code :
a sequence of Morse code found 48 minutes into the piece, spelling out "FUCK OFF RB" in reference to Virgin's Richard Branson, the man who had first signed him.
Source: Wikipedia
musicfans.stackexchange.com/users/131/Pat Dobson
The rhythm and timing in Tool's Lateralus contain numerous references to the Fibonacci sequence and the Golden Ratio: https://en.wikipedia.org/wiki/Lateralus_(song)
musicfans.stackexchange.com/users/63/Marek Grzenkowicz
(Very good answers above!)
There are so many examples of music communicating more information than mere artistic expression.
The only reason that the Romans developed the brass horn was to signal troop movements.
They made brass horns bigger, louder and implemented a set of musical motifs to order charge, retreat, etc.
They weren't interested in music at all, but the modern-day brass section owes a debt of thanks to the Roman army.
The same applies to other cultures using the drums, bagpipes, etc.
The psychological warfare aspect to these noisy instruments is secondary to communication among troops.
Church bells are another ubiquitous example: signaling time, weddings, emergencies, celebrations, etc.
Town bell towers indicate time, in fact Big Ben uses different variations of a melody to signal time every fifteen minutes.
In the modern era, the spacecraft Voyager included a CD recording of several great musical works, in an attempt to communicate some information about Earth to any civilization that discovers it (and succeeds at decoding it).
At my local university, I participated on a research team to create an algorithm that would synthesize an instrumental soundtrack to replace the continual beeping of the ECG.
The premise was that a melody could contain several elements, each tied to a different bio-feedback item.
Therefore, the overall status of a patient could be easily determined by the nurse upon his/her entering the patient's room and hearing the melody.
As a side-benefit, this soothing melody replaced the annoying beep of the ECG.
musicfans.stackexchange.com/users/2072/Everett Steed
Check out 'Bermuda Triangle' by Tomita, where a cryptic message is encoded within the audio.
You need special (obscure) hardware to decode the message.
According to isaotomita.net/recordings/bermuda.html
The computer encoded signals found on this album are in a format known as TARBEL.
Using this system, messages may be encoded in a recording via audio signals.
The TARBEL format was used as a way to save data onto an audio cassette recorder in the mid to late 1970s before the IBM PC and hard disk drives.
The sound is familiar to anyone who has used an old tape interface (lots of 'piii's and 'gaaa's!) and can be decoded with a computer programmed to recognise the TARBEL system.
The actual messages are Side A
THIS IS THE BERMUDA TRIANGLE,
OVER.
SLOW DOWN.
TARGET 50 MILES OFF SOUTH FLORIDA, A GIANT PYRAMID AT OCEAN BOTTOM.
Side B
THIS IS THE BERMUDA TRIANGLE, OVER.
LOOK OUT!
THE CYLINDRICAL OBJECT
JUST LIKE THE ONE EXPLODED OVER SIBERIA AND CRASHED INTO TUNGUSKA IN 1908, HAS JUST COME INTO THE SOLAR SYSTEM.
Even at the time of its release TARBEL was uncommon.
In fact, apart from this Tomita album, I've never heard of anyone else using it.
musicfans.stackexchange.com/users/2366/Brian THOMAS
Music is often dubbed 'the universal language', but language usually carries some information.  I know that music has many different notes, with letters and pitches assigned to each. Was there ever any instrumental (lyric-free) music written as a code to carry information, in any form? (numbers, letters, etc)   If so, can you please list the name, and artist/composer, if possible?  Thanks for your help.
Has any instrumental music ever been used to carry information?
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<history><classical-music><instrumental>
musicfans.stackexchange.com/questions/2264
musicfans.stackexchange.com/users/1047/Pyraminx
Examples of this include YYZ by Rush, the Bach Motif, which is a sequence of notes that spells out composer Johann Sebastian Bach's last name using note names (using the German names for notes, which include an "H"), references to the Fibonacci sequence and the Golden Ratio in the rhythm and timing Tool's Lateralus, and  'Bermuda Triangle' by Tomita, where a cryptic message is encoded within the audio. The songs YYZ by Rush  ,The Bach Motif, Tool's Lateralus and Bermuda Triangle are noted to carry some form of information. 
YYZ by rush Information like names, formulas and cryptic messages is shared through the use of notes, rhythm and timing. The examples given are The Bach Motif, Tool's Lateralus and Bermuda Triangle