This essay outlines some common properties of channels, infrastructure, and institutions. It analyzes the tense relation between channels and codes, on the one hand, and circulation and interpretation, on the other. It compares the assumptions and interventions of three traditions: cybernetics (via Claude Shannon), linguistic anthropology (via Roman Jakobson), and actor-network theory (via Michel Serres). By developing the relation between Serres's notion of the parasite and Peirce's notion of thirdness, it theorizes the epi-function served by the menagerie of entities who live in and off infrastructure: enemies and noise, meters and sieves, pirates and exploits, catalysts and assassins. By extending Jakobson's duplex categories (shifters, reported speech, proper names, metalanguage) from code-sign relations to channel-signer relations, it describes four reflexive modes of circulation that any network may involve: source-dependent channels, signer-directed signers, self-channeling channels, and channel-directed signers. And it relates the commensuration of value to the enclosure of disclosure.[media, infrastructure, circulation, translation, enclosure.]