Master timer

945,686. Reading paper tape. INTERNATIONAL BUSINESS MACHINES CORPORATION. July 13,1960 [July 13, 1959], No. 24437/60. Heading G4M. Means are provided for storing a single character inadvertently read from paper tape due to overshooting the read station after a stop order The machine is assumed to be such that only one character does so overshoot. If the tape has feed holes, under normal reading conditions switches 10a, 10b are set as shown in the Figure, the holes are sensed by photo-electric means 11a to 11h which conditions and gates 14a to 14h, and the sensing of the feedhole sets trigger 21. When the feedhole is past the sensing means 17, line 24 conditions and gate 25 to set a trigger 27 starting a clock 29 which opens the read-in gates 14 causing triggers 12a to 12h appropriate to the sensed holes to be set, opens the read-out gates 30 to pass the character for interpretation, resets the triggers 12 and the triggers 21, 27. On receipt of a stop signal and gate 25 is deconditioned and should a character then pass the read station and circuit 38 is conditioned by the feedhole to open the read-in gates 14, allowing the character to be registered. If the tape has no feedholes or pinhole feedhole switches 10a, 10b are set to the other position. Switch 10b holds the read-in gates permanently open and the sensing means thus act directly on the register 12. Hole sensing operates trigger 21 and when the character is past line 24 rises to condition and circuit 25. If the Go signal is not present, due to the setting of switch 10b any overshoot character is read into the register 12. If machine tolerances are good the read-in gates and clock may be omitted and the read-out gates opened by and circuit 25.