Patent GB-714431-A (GB)
Title: Improvements in or relating to teleprinters
IPC: H04L17/00
Filed: 1951-08-07
Abstract: 714,431. Type-printing telegraphy. SIEMENS & HALSKE AKT.-GES. Aug. 7, 1951 [Aug. 5, 1950], No. 18618/51. Class 40 (3) In a teleprinter comprising case-shift arrangements for different function groups, for example a letter group and a figure group, for the multiple employment of the signal code combinations, there are provided further shift arrangements for the change-over to additional functions which can be initiated by selected code combinations of signal elements, said arrangements being operable solely when the teleprinter is in the figureshift condition and only by particular code combinations of signal elements corresponding to letters in the letter group, and in addition there are included further locking devices dependent on the change-over to the additional functions and adapted to lock the two normal function groups against operation. Transmitting-arrangements. Fig. 5a shows the locking bars Sp1, Sp2 positioned to allow transmission in the lower case group, levers corresponding to letters, such as Q, being operable in addition to the key levers corresponding to lettershift Bu, figure-shift Zi, line shift Zl, carriagereturn WR and word space Zwr. On depressing the key Zi for the shift to figures, the locking bar Sp1 is moved to the left, with the locking bars Spl, Sp2 in the positions shown in Fig. 5b, the !etters levers such as Q, and also the levers a, f allocated to the additional functions are locked against operation. The levers assigned to lettershift, carriage-return &c. are still operable and, in addition to numeral levers, those allocated to "who are you?", Werda, and the bell signal KL can be actuated. When a lever Fu corresponding to the auxiliary shift signal which may be one of the spare code combinations in the usual upper-case dispositions, the second locking lever Sp2 is moved to the left and with the bars Spl, Sp2 in the position shown in Fig. 5c, the levers a, f controlling auxiliary functions can be operated, all other levers except those for lettershift and figure-shift being locked against actuation. The operation of the figure-shift key Zi restores the keyboard to the upper case condition and the actuation of the letter-shift key Bu moves both locking bars Sp1, Sp2 to the right to restore the keyboard to the lower case condition. In modifications, the lever allocated to bell signal may also effect the change of the keyboard to the subsidiary shift condition or this code combination in the upper case condition may be used as the auxiliary shift signal, and the bell may be operated as one of the auxiliary functions in the third case group. In a further modification, Fig. 6 (not shown), the bell lever may be used to restore the keyboard to the figure-shift condition, the letter-shift lever being freed for operation to return the keyboard to the lower-case condition if necessary. Receiver-arrangements.-The locking operations of the bars Spl, Sp2 are generally similar to those effected at the transmitter apart from the arrangement that the letters levers except D, J, corresponding to " who are you? " and bell, must also be operable in the upper case group to effect printing from the appropriately positioned typewheel or type-basket. When the auxiliary shift signal is received so that the lever Fu is operated, both locking bars Sp1, Sp2 are moved to the left so that levers a, f ... controlling auxiliary functions can be actuated. The reception of the figure-shift signal moves bar Zi downwardly to restore the selecting mechanism to the upper or figure condition, whilst the letters shift signal operating bar Bu restores the locking bars Sp1, Sp2 to the right to the position shown in Fig. 7c so that letters are printed. In a modification, Fig. 8, the second locking bar Sp2 is latched in its left-hand position by a detent Ki and is not operated by the figure-shift or letter-shift bar. It is released for return to its right-hand position by an auxiliary bar Hi operated to release the detent Ki by a projection engaged by a bar, such as f, actuated to initiate an auxiliary function. A similar unlocking arrangement may be employed for the bar Sp2 at the transmitter. The additional functions may be the printing of letters from a different or unusual alphabet, the bars relating to C.R. line-shift and space being reserved for those operations in the three case conditions of the teleprinter. The arrangement may be extended to four or more case groups with suitable choice of the code combinations for the successive auxiliary shift signals.