When an AKP was used to punch data from source documents, it was quite likely that errors might be made. To overcome this a completed batch of cards would be placed in the magazine of a second AKP and its operator would key in the data from the same documents all over again. However, the cardstop of this machine was switched to the "Verify" position and this allowed the card to pass into the punching station half a width of a hole more than a card entering a machine set to the "Punch" position. Thus, if the verify operator punched identical keys to the punch operator then the card would end up with all the holes having become little slots with rounded ends. If either operator made a mistake in her keying then a round hole would be the result. The only flaw in this system was in the most unlikely case of both operators making the identical error. After this verifiying punching the cards were sent to the Auto Verifier to check that no round holes remained in the punched fields. The AV had a sensing-only card feed with special flattened sensing pins pins which would pass through slotted holes but be obstructed by any round holes, and any so detected would be collected by an errors box. These cards were subsequently inspected by the operator and by reference to the source documents the mistake could be found and eliminated.The columns to be checked by the AV could be individually selected as some cards might properly could contain other fields with round holes only.This machine ran at the surprisingly high rate of 200 cards per second.

The Reproducer

This was an additional machine required because occasionally there was a need to duplicate a particular group of cards although presently the author cannot recall when this would have been neccessary in the MATS Unit application. It consisted of two card feed systems mounted one above the other. The upper one sensed the holes in the source cards with sensing pins and transmitted this information via a "Connection Box" downwards to the setbar unit of the punching card feed track below, the magazine for which was loaded with blank cards. Both tracks ran at the same speed and the magazine of the lower track was loaded with blank cards. The removable connection box was a skeleton die cast cage fitted with perforated plates top & bottom. Straight very stiff thin rods fitted upper to lower holes for one-to-one reproduction