Source : Free On-Line Dictionary of Computing

EOU
     
         The mnemonic of a mythical {ASCII} control
        character (End Of User) that would make an {ASR-33} {Teletype}
        explode on receipt.  This construction parodies the numerous
        obscure {delimiter} and control characters left in ASCII from
        the days when it was associated more with wire-service
        teletypes than computers (e.g. {FS}, {GS}, {RS}, {US}, {EM},
        {SUB}, {ETX}, and especially {EOT}).  It is worth remembering
        that ASR-33s were big, noisy mechanical beasts with a lot of
        clattering parts; the notion that one might explode was
        nowhere near as ridiculous as it might seem to someone sitting
        in front of a {tube} or flatscreen today.
     
        [{Jargon File}]
     
        (1996-06-29)