Commercial code (communications)
Encyclopedia
In telecommunication
Telecommunication
Telecommunication is the transmission of information over significant distances to communicate. In earlier times, telecommunications involved the use of visual signals, such as beacons, smoke signals, semaphore telegraphs, signal flags, and optical heliographs, or audio messages via coded...

, a commercial code is a code
Code
A code is a rule for converting a piece of information into another form or representation , not necessarily of the same type....

 once used to save on cablegram costs . Telegraph (and telex
Telex
Telex may refer to:* Telex , , a communications network** Teleprinter, the device used on the above network* Telex , a Belgian pop group...

) companies have always charged based on the length of the message sent—and this has not changed since the 19th Century. To this day telex messages are charged by the word.

When telegraph messages were the state of the art in rapid long distance communication, elaborate commercial codes which encoded complete phrases into single words (commonly five-letter groups) were developed. For example "words" as BYOXO ("Are you trying to weasel out of our deal?"), LIOUY ("Why do you not answer my question?"), BMULD ("You're a skunk!"), or AYYLU ("Not clearly coded, repeat more clearly.").
A "dictionary" of such "words" is a codebook
Codebook
A codebook is a type of document used for gathering and storing codes. Originally codebooks were often literally books, but today codebook is a byword for the complete record of a series of codes, regardless of physical format.-Cryptography:...

. For telegraph offices that would not accept messages with non-words such as AYYLU, codebooks were compiled with only real words as codewords, sometimes using words from multiple accepted languages to expand the supply even though all the plaintext phrases were in one language.

Such commercial codes became obsolete in the late 20th century. They were replaced by much simpler (although admittedly more long-winded) codes such as Morse Code Abbreviations
Morse Code Abbreviations
Morse code abbreviations differ from prosigns for Morse Code in that they observe normal interletter spacing; that is, they are not "run together" the way prosigns are. From 1845 until well into the second half of the 20th century, commercial telegraphic code books were used to shorten telegrams, e.g...

 and Ten-code
Ten-code
Ten-codes, also known as ten signals, are code words used to represent common phrases in voice communication, particularly by law enforcement and in Citizens' Band radio transmissions....

 and Q code
Q code
The Q code is a standardized collection of three-letter message encodings, also known as a brevity code, all of which start with the letter "Q", initially developed for commercial radiotelegraph communication, and later adopted by other radio services, especially amateur radio...

, and also by more compact automatic data compression
Data compression
In computer science and information theory, data compression, source coding or bit-rate reduction is the process of encoding information using fewer bits than the original representation would use....

 algorithms.

In this context, "commercial code" (used purely to save cable costs, where the people communicating didn't care if anyone else could read their messages) is distinguished from similar "secret codes" used in cryptography
Cryptography
Cryptography is the practice and study of techniques for secure communication in the presence of third parties...

.

Purpose

Initially the necessity for Commercial Codes was to save money. There was a boom in commercial telegraphy in the US (and Europe) from the 1880s into the 1920s, but messages were initially not cheap to send. This industrial sector was really where some of the first academic experimentations in lossless data compression
Data compression
In computer science and information theory, data compression, source coding or bit-rate reduction is the process of encoding information using fewer bits than the original representation would use....

 and error correction (using checksum
Checksum
A checksum or hash sum is a fixed-size datum computed from an arbitrary block of digital data for the purpose of detecting accidental errors that may have been introduced during its transmission or storage. The integrity of the data can be checked at any later time by recomputing the checksum and...

s and check digit
Check digit
A check digit is a form of redundancy check used for error detection, the decimal equivalent of a binary checksum. It consists of a single digit computed from the other digits in the message....

s) took place.

Elaborate commercial codes were developed that encoded common phrases as words or numbers. There were even a few commercial rating agencies (possibly linked to the book trade) that rated codebooks for their efficiency but these had more or less ceased operation by the mid-1930s.

Another aim of the telegraph codes was to reduce the risk of misunderstanding by avoiding having similar words mean similar things. There was also the goal of secrecy (or at least telecommunications communications privacy), as telegraph operators could potentially use information garnered from commercial and some kinds personal messages for their own personal profit.

Examples of these codes include the A.B.C Telegraphic Code, Bentleys Second Phrase Code, Slater's Telegraphy Code (1916), Western Union Universal Codebook (1907) and Unicode (1889).

In addition to more general commercial codes, there were a number of codes targeted at particular industries e.g. railways, timber, shipping, cotton and diplomats (the Western Union Universal Codebook was used by some US Embassies on a limited basis between 1905 and the mid 1930s).

Mechanics

In codes such as the A.B.C. Telegraphic code, code words could contain what would be recognized today in programming terms as parameters e.g. in the 'Freight and tonnage requirements' section, antitacte means Mozambique, loading at not more than two places, to ____, steamer for about ____ tons general cargo at ____ per ton on the d/w capacity to cargo.

The telegrapher would then fill in the 3 parameters, the destination, the number of tons and the price per ton.

The regulations of the International Telegraph Convention distinguished between 'code telegrams' which it describes as 'those composed of words the context of which has no intelligible meaning' and 'cipher telegrams' which it describes as 'those containing series of groups of figures or letters having a secret meaning or words not to be found in a standard dictionary of the language'.

Codes such as the A.B.C. Telegraphic Code, therefore, included both numbers and code words so the user could choose between the two.

Examples

Example code words:
  • From the A.B.C Telegraphic Code (5th Edition)
    • paromella — in leaving the dock (harbour) struck the pier, damaging the stern
    • arimaspen — Phaeton with 6 B.H.P. two cylinder motor to seat four passengers speed — miles per hour
    • haubarer — Charterers will allow the option of carrying horses for ship's benefit

  • From Bentley's Complete Phrase Code
    • oyfin — has not been reinsured
    • azkhe — clean bill of health
    • atgam — have they authorised?

  • From the telegraphic cipher code specially adapted to the cotton trade
    • dress — the supply from India will be less than expected
    • insane — at what price, free on board and freight, can you offer us cotton for shipment by steamer sailing this week?
    • puncher — we anticipate rate of interest will be reduced by Bank of England

  • From 'Unicode' (which, unlike the others, was intended for domestic use in addition to commercial; unrelated to the Unicode
    Unicode
    Unicode is a computing industry standard for the consistent encoding, representation and handling of text expressed in most of the world's writing systems...

     computing standard)
    • dionysia — Amputation is considered necessary
    • annosus — Confined yesterday, Twins, both dead, Mother not expected to live
    • cognosco — Dining out this evening, send my dress clothes here


In computer network
Computer network
A computer network, often simply referred to as a network, is a collection of hardware components and computers interconnected by communication channels that allow sharing of resources and information....

ing, commercial code could be thought of as the application layer
Application layer
The Internet protocol suite and the Open Systems Interconnection model of computer networking each specify a group of protocols and methods identified by the name application layer....

, Morse code as the data link layer
Data link layer
The data link layer is layer 2 of the seven-layer OSI model of computer networking. It corresponds to, or is part of the link layer of the TCP/IP reference model....

 and the binary line code
Line code
In telecommunication, a line code is a code chosen for use within a communications system for baseband transmission purposes...

 as the physical layer
Physical layer
The physical layer or layer 1 is the first and lowest layer in the seven-layer OSI model of computer networking. The implementation of this layer is often termed PHY....

. However, fundamental differences between telegraphy and networking mean that some layers of the OSI model
OSI model
The Open Systems Interconnection model is a product of the Open Systems Interconnection effort at the International Organization for Standardization. It is a prescription of characterizing and standardizing the functions of a communications system in terms of abstraction layers. Similar...

 have no distinct analogs (namely the presentation
Presentation layer
The presentation layer is layer 6 of the seven-layer OSI model of computer networking and serves as the data translator for the network. It is sometimes called the syntax layer.-Description:...

, session
Session layer
The session layer is layer 5 of the seven-layer OSI model of computer networking.The session layer provides the mechanism for opening, closing and managing a session between end-user application processes, i.e., a semi-permanent dialogue. Communication sessions consist of requests and responses...

, transport
Transport layer
In computer networking, the transport layer or layer 4 provides end-to-end communication services for applications within a layered architecture of network components and protocols...

, and network layer
Network layer
The network layer is layer 3 of the seven-layer OSI model of computer networking.The network layer is responsible for packet forwarding including routing through intermediate routers, whereas the data link layer is responsible for media access control, flow control and error checking.The network...

s). The responsibilities of these layers—which include error correction, addressing, delivery, and connection management—were jointly handled by telegraph operator protocol.
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