The reproducer (Fig. 9) has 2 independent card channels, the cards not mingling in any way, called the _reading channel_ and the _punching channel_. We can run the machine with only the punching channel working; in fact, IBM equips some models only with the punching channel, particularly for “summary punch” operation. The machine is timed so that, when any card is at the middle station in either channel, then the next preceding card is at the latest station, and the next following card is at the earliest station. At 5 stations, the machine reads a card. At the middle station of the punching channel, the machine punches a card. Using a many-wire cable, we can connect the tabulator to the reproducer and so cause the tabulator to give information electrically to the reproducer. This connection makes possible the “summary punch” operation. Here is an instance with punch-card machines where, in order to transfer information from one machine to another, we are not required to move cards physically from one machine to another. Collator The collator is a machine that arranges or _collates_ cards. It is particularly useful in selecting, matching, and merging cards. The collator (Fig. 10) has 2 card channels which join and then fork into 4 channels ending in pockets called _Hoppers_ 1, 2, 3, and 4. The 2 card feeds are called the _Primary Feed_ and the _Secondary Feed_. Cards from the Primary Feed may fall only into the first and second hoppers. Cards from the Secondary Feed may fall only into the second, third, and fourth hoppers. The collator has 3 stations at which cards may be read. [Illustration: No.1--Selected primaries No.2--Merged cards and unselected primaries No.3--Separate secondaries not selected No.4--Selected secondaries FIG. 10. Collator.] IBM can supply additional wiring called the _collator counting device_. With this we can make the collator count cards as well as compare them. For example, we could put 12 blank cards from the Secondary Feed behind each punched-card from the Primary Feed in order to prepare for some other operation. Calculating Punch The calculating punch was introduced in 1946. It is a versatile machine of considerable capacity. It adds, subtracts, multiplies, and divides. It also has a control over a sequence of operations, in some cases up to half a dozen steps. This machine (Fig. 11) has one card channel with 4 stations called, respectively, _control brushes_, _reading brushes_, _punch feed_, and _punching dies_. At station 1, there are 20 brushes; we can set these by hand to read any 20 of the 80 card columns. At station 2 there are 80 regular reading brushes. At station 3 the card waits for a part of a second while the machine calculates, and, when that is done, the card is fed into station 4, where it is punched or verified. The multiplying punch is an earlier model of the calculating punch, without the capacity for division. [Illustration: FIG. 11. Calculating punch.] Tabulator