four characters in each group was then selected based on the zone impulse (0, 11, 12 or none) for that character position. This selection happened at the same time the type wheel was driven against the ribbon. The timing of the zone impulse selection was controlled by a complex set of linkages and electromagnets called the Analyzer, one for each of the 120 print positions. Each type wheel also emitted an impulse (called "echo") for the character actually printed. The control panel could be wired so the echo impulses were accumulated for totals; report totals then reliably reflected what had actually been printed. Mechanical systems including the card reader, printer, counters and storage units were all driven by a single motor, which also drove an oil pump and a generator that provided 46-volt power for the electrical logic. This included about 900 relays which were mounted on three swing-out gates. The control panel had a matrix of 43 by 52 holes, most of which were assigned. The 407 was available in a model that could read 100 cards per minute, and one reading 150 cards per minute. The former had a relay which would inhibit every third card feed cycle (giving the machine a characteristic "shrink-shrink-thunk" sound). It was possible to insert a folded card between that relay's contacts to "overclock" the slower model to the faster speed. Market impact The 407 rented from $800 to $920 per month ($ to $ per month in dollars), depending on the model. Its print mechanism was used in the IBM 716 introduced in 1952 with the IBM 701 computer, and the 716 was used with many machines in the IBM 700/7000 series. The 407 itself was adapted as an input/output unit on the IBM 650. Later, the 407 print mechanism was used in the IBM 1132 line printer, part of the low cost IBM 1130 computer system, introduced in 1965. The IBM World Trade Corporation marketed Computing Accounting Machines (CAM), variations of either the IBM 402 or 407 with an attached computer. CAM variations of the 407 included the IBM 421, 444, and 447. See also IBM 402 References External links Columbia University Computing History: The IBM 407 IBM Archive: IBM 407 photo (in photo, the box at left side is not part of the basic 407) IBM Archive: IBM 407 control panel photo Audio clip of IBM 407 in operation 407