An electronic apparatus and code conversion method for use in a data terminal system incorporating a modified type head electric typewriter as the data input-output device. A single timing sequence automatically controls all code converting operations of the terminal for both transmitting and receiving data. In a transmit cycle of the timing sequence, a keyboard code of the typewriter is converted to a selected one of a number of communications line codes which is then transmitted over the line. In a receive cycle of the timing sequence, the line code is then further converted into a suitable print code for operating the print or function mechanisms for the typewriter. When the terminal is receiving data, only the receive cycle of the complete timing sequence is effective. All conversions are made by means of a master register which is gated in parallel through code conversion logic gates, or a read-only memory, back into the register. The states of the master register flip-flops containing the print code determine which of a series of electromechanical actuators are activated to operate the print mechanism of the typewriter. Additionally, a method and apparatus is disclosed for generating a six bit line code from only three outputs of the read-only memory.
An auxiliary translator is added to the main translator of a system for analysing telegraph characters. The auxiliary translator has a number of inputs equal to the number of different telegraph characters of the alphabet employed and a plurality of outputs each providing a binary value made up of a number of binary elements lower than the number of binary elements making up the telegraph character. This arangement reduces the size of the main translator employed in prior art systems to analyse telegraph characters.
An asynchronous buffered interface for interconnecting a data processing apparatus adapted to communicate in serially coded ASCII data format and a terminal comprising a printer and a keyboard, both of which are adapted for data communication in parallel format.
An automatic teletypewriter is provided. The teletypewriter includes a keyboard having alpha and numeric characters and includes means to utilize the numeric character keys for dialing into the telex network. The teletypewriter also automatically keeps count of the characters generated on each line and generates a carriage return-line feed signal at the end of each line if not directed to do so.
A bi-directional translator may operate in a transmit non-translate mode or a transmit translate mode. In the transmit translate mode input characters in a first code appearing on a first input bus address a read only memory to read out second code translations of the characters on a first output bus. In the transmit non-translate mode the input characters are gated to the first output bus without addressing the memory. The translator may also operate in a receive translate mode or a receive non-translate mode. In the receive translate mode characters in the second code appearing on a second input bus address the memory to read out first code translations of the characters on a second output bus. In the receive non-translate mode characters in the first code appearing on the second input bus are gated to the second output bus without addressing the memory. In the first code the case of each character (upper or lower) is determined by a bit position within the character whereas the second code requires two special case characters which determine the case of the characters following them. The translator inserts the required case characters in the outgoing character sequence when operating in the transmit translate mode, and eliminates the case characters from an incoming character sequence when operating in the receive translate mode. Since the first code includes more characters than the second code, provision is made for recognizing characters of the first code having no equivalent in the second code, and preventing any character output in response to such a recognized character.
A data terminal has a keyboard capable of encoding data. A switch determines whether a diode matrix will encode keyboard entries in Baudot or ASCII code. A modem couples the encoded keyboard data to telephone lines for transmission to another terminal station. Data may be received by the terminal in either Baudot or ASCII code. The received data is translated to alpha-numeric video signals that may be displayed on a conventional television receiver.
