743,696. Statistical-apparatus. INTERNATIONAL BUSINESS MACHINES CORPORATION. July 31, 1953, No. 21266/53. Class 106 (1). A verifying machine for checking data representing holes punched in a tape is characterized in that means are provided for feeding forward the tape step-bystep whenever verifying circuits have detected identity between the data punched in the tap and a corresponding data key depressed by the operator. Fig. 1 shows a keyboard with twelve keys T1 &c. and three additional keys 1, 2, 3. The feed mechanism of tape 7 comprises a sprocket driving wheel 5 driven by gears 4 and 12. A pawl 10 rotates a ratchet wheel 9 step-by-step to drive the tape in step-by-step fashion whenever electromagnet 11 is de-energized through the action of spring 10b, Fig. 2. Fig. 2 also shows diagrammatically a pin sensing station 19 and a punching station 20. A set of punch pins operated by a plate 21 punch the tape whenever punch magnet 22 is energized. A second set of punches may be actuated by plate 41 alongside plate 21, the plate 41 being operated by a punch magnet 40. A printing unit 42 is provided, operated by pivot magnet 43. When the armature 44 of pivot magnet 43 is attracted stylus 45 contacts the tape which by its movement causes the marking of two lines 46. To perform a verification operation, the operator places tape 7 so that column A is positioned under the sensing pins of station 19 and pointer 14 is correctly aligned to a position corresponding to column A, by disconnecting friction clutch 18. Synchronism key 1 is depressed and if the tape 7 and pointer 14 are correctly positioned the tape advances one column to bring the first column under the reading station 19. If column B carries no hole the operator checks that the column in blank by depressing key 2. If column B holds a special punched hole the operator must depress key 3. The tape is then fed forward to bring the first data bearing column under the reading station. Assuming that a " 1 " hole is punched in the tape, if the operator depresses the T1 key the tape will be advanced one step immediately T1 key is released. If, however, an error occurs for example the operator depresses key 0 instead of 1 a relay 27, Fig. 3, will pick up and a signal light 28 will glow. Relay 27 remains closed until error cut-out key 34 is depressed. If after this mistake the correct key is depressed the tape is fed forward one step. If the tape is wrongly punched with, say 0 instead of 1, when T1 key is depressed relay 27 is held and the signal light will glow until error cut-out key 34 is depressed as previously. Depression of key 34 a second time causes relay 27 to drop out and relay 35 to pick up, preventing the tape feed until error key 34 is depressed a second time. When the operator reaches the last column he must check that column C is blank, by means of spacing key 2. If a hole has been wrongly punched in this column relay 27 is caused to pick up as described previously. When the tape moves forward again the pointer is in position A while column C is under the punching station 20 and magnet 22 is picked up, causing the lowering of plate 21 with a set of punch pins corresponding to the erroneous groups or alternatively another combination of holes may be punched when the tape has no error by actuation of magnet 40 instead of magnet 22. The pick up of punch magnet 22 causes the pick up of relay 39 through the making of contact 22a controlled by relay 22. The purpose of this relay is to unlatch contact 37a held by latch 38, thus, as soon as the verification punching has been done the normal circuits are re-established. After a certain number of columns have been checked the machine stops without the signal lamp 28 glowing. This condition tells the operator that the group does not hold 25 columns unless special circuits are made to prevent this sequence from occurring. The magnet 43 is provided for the purpose of controlling the lowering of two pencils to mark two traces along the tape whenever an error is detected. For this purpose hub 47 is connected to hub 49 and hub 48 to 50. As soon as an error is detected relay 37 picks up; as a result of second verification relay 51, in parallel with relay 37, also picks up through the wiring between hubs 47 and 49. The pick up of this relay 51 causes the making of contact 51a which remains latched by means of pent 52. When the operator depresses key 34 the tap feeding takes place and as the pencils are lowered two lines are marked on the tape until magnet 43 drops out through the action of relay 53 which causes unlatching of the armature of relay 51.