Aviation Electronics Technician 1 - Historic Naval Ships Association

Teleprinter Secure InterfaceMounted under the TTY keyboard, this unitprovides remote selection of secure or clear TTYoperation. By placing the red guarded TTY/TPR switchto the BYPASS position, the operator closes a relay tobypass the TSEC/KW-7.Communications Interface No. 1Figure 1-22.-COMM interface No. 1.over voice radio. Switches on the front of the boxprovide control over data conversion,TSEC/KW-7 Security UnitThis unit provides encryption and decryption of thebaudot code. It is usedoperation.whenever the teletype is inTSEC/KWX-7 securityUnit (RCU)Unit Remote ControlThis unit is located next to the TTY keyboard andenables the operator to control the TSEC/KW-7 withouthaving to leave his/her seat.This unit (fig. 1-22) connects the TTY system withthe central computer. It converts the baudot code into30-bit, parallel, binary computer language. The switchesand controls on the front of the interface are inoperativein the OPERATE mode.TELETYPE SYSTEM OPERATIONFigure 1-23 shows the teletype system blockdiagram.Off-line operation of the TTY system requires theoperator to select an appropriate frequency on the HF-1,HF-2, or UHF-2 control panel and to select TTY modeon the communications selector panel. The selectedradio is automatically mode forced into a datatransmission mode. The operator selects words perminute (WPM) speed (normally 100) and TTY on theHSP, and DIR SEND on the TTY keyboard. Phasing theTSEC/KW-7 sends a synchronization signal that isreceived by all other units on the frequency. Once allunits are synchronized, they are ready to accept data.When a key is depressed on the TTY keyboard, thecorresponding baudot code is generated. This is sent toFigure 1-23.-Teletype system block diagram.1-24