02 March 2014

Alexander Graham Bell v. Samuel F. Morse

I just read again for the umpteenth time that telephony displaced telegraphy. Let's put that myth to rest. It's just the other way around.

Alexander Graham Bell's 1876 patent for the telephone had a flaw that would eventually prove fatal for its technology: its signals were analog, varying electrical voltage and amplitude to convey the variances inherent in human speech.

Telegraphy, on the other hand, was designed nearly from the beginning using binary on/off signaling. In 1874, Ă‰mile Baudot improved on earlier telegraphy codes such as the Morse code by devising a 5-bit telegraphy code system, still binary in form but treating each sequence of 5 on/off bits as a "code page" that could transmit a far richer character set than Morse code. The Baudot system also incorporated multiplexing, allowing multiple messages to be transmitted over the same wire concurrently. Baudot's code was improved  by others and morphed into  International Telegraph Alphabet No. 2 (ITA2), which remained the major teletype telegraphy code until ASCII was introduced. (I'll omit discussion here of the 6-bit teletypesetter code that played such a pivotal role in the evolution of automated word processing.)

Analog telephony signals clashed fundamentally with computerized automation in that computers are dependent on binary notation and binary math, which can't be usefully expressed in an analog signal. Analog signals also require incredible bandwidth, compared to binary signals.

And so it came to pass that the telephone industry made a transformation over the last few decades from analog to digital signaling, from telephony to telegraphy. We still call that thing you talk into a telephone, but in fact it's a telegraph sending and receiving unit, with binary telegraph signals converted to and from analog audio for your listening dis/pleasure.

Telephony is deader than a door-nail. Telegraphy won.

Update (4 October 2014): The error persists. See Comcast Corp. v. Dept. of Rev.,  356 Or 282, 293 n. 5 (2014). ("The legislature also amended the definition of 'communication; in ORS 308.505(3) to remove the reference to 'telegraph communication,' see Or Laws 2009, ch 128, § 3, which by then effectively had ceased to exist.")

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