A Model 20 Teletype machine with a paper tape punch ("reperforator") was installed at subscriber newspaper sites. Originally these machines would simply punch paper tapes and these tapes could be read by a tape reader attached to a "Teletypesetter operating unit" installed on a Linotype machine. The "operating unit" was essentially a box full of solenoids that sat on type of the Linotype's keyboard and pressed the appropriate keys in response to the codes read from the tape, thus creating type for printing in newspapers and magazines.[36]