ES353111A1 - Key-operated teleprinter - Google Patents

Abstract

A keyboard transmitter has a separate key for each symbol and includes means for automatically inserting case shift signals in to the stream of transmitted characters. On depression of a key To is closed, T1-T5 are selectively closed to represent the character, and T6 is closed if the character is a Figures case character. On closure of To the character represented by T1-T6 is transferred via stores A1-A6 and B1-B6 to store C1-C6. Two further characters can be stored in A1-A6 and B1-B6, whereupon electromagnet Ms is energized to prevent further key operation. When Co is at 1 (i.e. when a character is in C1-C6) a time base unit I generates successive pulses t 1 -t 7 . During t 1 the character in C1-C6 is passed to store S1-S6, the characters in A1-A6 and B1-B6 passed to B1-B6 and C1-C6 respectively, and start polarity applied to the transmission line L. During t 2 -t 6 the content of S1-S5 is passed serially to line, and during t 7 Stop polarity is applied to the line. Subsequently stored characters are transmitted in the same way. When no character is to be transmitted the line is held at Stop polarity. The case bit (from T6) stored in S6 of a character to be transmitted from S1-S5 is passed to store K, and any change in state of K, indicating that the character to be transmitted is not in the same case as the character just transmitted, causes H to prevent read out of S1-S5 and a LTRS or FIGS character as appropriate to be automatically transmitted by way of gates UL2, 3, 5, 6. Should C1-C5 contain a character which has the same significance in either case (e.g. Carriage Return) store S6 is prevented from changing state when the character in C1-C5 is passed to S1-S5, and consequently no case shift character is inserted prior to transmission of this character. Repetition of a character is initiated by closure of T7. This sets W to inhibit gate UZ so that read out from C1-C6 to S1-S6 is prevented. Time base 1 now generates t 1 -t 7 continuously and the character in S1-S6 is passed to line repeatedly until T7 is released.