Patent GB-539745-A (GB)
Title: Improvements in or relating to electric calculator equipment
IPC: G06F5/00
Filed: 1940-02-16
Abstract: 539,745. Calculating-apparatus. STANDARD TELEPHONES & CABLES, Ltd. (Hatton, W., Haigh, L. B., and Kozma, L.). Feb. 16, 1940, No. 2980. [Class 106 (i)] An electrically-operated machine comprises means for receiving signals over a two-wire line representing a problem to be solved and means for entering the numerical data and the operation signs represented by the said signals into a calculating apparatus. The invention also includes means for transmitting over the same or another two-wire line signals representing the solution of the problem. In the arrangement shown in Fig. 1 the receiving and transmitting means is connected through the leads 1-15 on the right to a calculating apparatus as described in Specification 525,330 and on the left to a teleprinter over a two-wire line ab. The lead 15 is an additional lead connected to battery and a relay which when operated indicates that the apparatus is not ready to receive a problem. The circuit also includes a start-stop receiver as described in Specification 524,917, [Group XL], and a code sender as described in Specification 520,548, [Group XL]. The startstop receiver is adapted to receive signals sent by the teleprinter and by means of its code relays CIA ... CIE, helping relays CTA ... CTE, a digit relay DI or an operation sign relay OS transmits the coded signals to the in-put wires 2-7 of the calculator. The output wires 8-11 of the calculator co-operate with output relays OPA ... OPD and OC and with code changing relays COA-COE, COH, COK, COL, CON, COO and DE to control the contacts of the code sender and transmit the signals representing the solution to the teleprinter. The operation of a switch (not shown) to connect the teleprinter to the calculator energizes relays PC, OR and thereupon relays LH, SL, RS, EH, PB and PL and connects the motors CSM, CRM of the code sender and the start-stop receiver to the mains. Relay EL operates and energizes relay CB to prepare for the " figure shift " signal to the teleprinter. The calculator is connected over the wire 1 when the contacts lh 4  are closed and in response to this signal battery is applied to the four wires 8 ... 11 to operate relays OPA ... OPD and OC. Relays PR, FS, BE, FC, FO and SS operate to transmit the " figure shift " signal through the code sender to the teleprinter. Three full stop signals are sent to the teleprinter upon the operation of the full stop relay DE. The printing of three full stops on the teleprinter is a signal to the operator that he may submit a problem to the calculator. The entry of the data is controlled by the relays OT, CCA and a combination of the relays CIA ... CIE and helping relays. After the first entry the kind of operation signal is sent and then the second entry and so on. When the " equals " signal is sent the solution is transmitted digit by digit over the relays OC, OPA ... OPD and code changing relays COO, COA, COB, COC, COD, COE, COH, COK, COL, CON. The circuit may be adapted to a teleprinter exchange system for use by a number of operators. Accounting system.-The circuit arrangement described may be used in banks as shown in Fig. 2 wherein operators ST 1 , ST 2  provided with teleprinters TP and dialling equipment DL are linked to magnetic tape recorders MTR 1  ...  3  for the different account through switches SW 1 , SW 2  and an amplifier OA. At a convenient time the records are read and signals sent through a switch SW 2  to code receivers PHR associated with a calculator CAL and transmitted through the code sender PHT to a tabulator TB of teleprinter type. A suitable form of tape recorder is shown in Figs. 3 and 4 and comprises a steel wire 3 wound round a metallic cylinder 1 driven by a constant speed motor and passed in proximity to an erasing magnet EM and recording and reproducing signal magnet RM.