TELETYPE SYSTEM OPERATION

Figure 1-22.-COMM interface No. 1. over voice radio. Switches on the front of the box provide control over data conversion, TSEC/KW-7 Security Unit This unit provides encryption and decryption of the baudot code. It is used operation. TSEC/KWX-7 security Unit (RCU) whenever the teletype Unit Remote Control is in This unit is located next to the TTY keyboard and enables the operator to control the TSEC/KW-7 without having to leave his/her seat. Teleprinter Secure Interface Mounted under the TTY keyboard, this unit provides remote selection of secure or clear TTY operation. By placing the red guarded TTY/TPR switch to the BYPASS position, the operator closes a relay to bypass the TSEC/KW-7. Communications Interface No. 1 This unit (fig. 1-22) connects the TTY system with the central computer. It converts the baudot code into 30-bit, parallel, binary computer language. The switches and controls on the front of the interface are inoperative in the OPERATE mode. TELETYPE SYSTEM OPERATION Figure 1-23 shows the teletype system block diagram. Off-line operation of the TTY system requires the operator to select an appropriate frequency on the HF-1, HF-2, or UHF-2 control panel and to select TTY mode on the communications selector panel. The selected radio is automatically mode forced into a data transmission mode. The operator selects words per minute (WPM) speed (normally 100) and TTY on the HSP, and DIR SEND on the TTY keyboard. Phasing the TSEC/KW-7 sends a synchronization signal that is received by all other units on the frequency. Once all units are synchronized, they are ready to accept data. When a key is depressed on the TTY keyboard, the corresponding baudot code is generated. This is sent to Figure 1-23.-Teletype system block diagram. 1-24