SHIPBOARD TELEPRINTERS

SLOW 45.5 BAUD 60 WPM 55 BAUD 75 WPM FAST 75 BAUD 100 WPM Figure 1-27.—CV-483 CRT signal patterns. View (A) shows a properly tuned signal, view (B) frequency is too high, view (C) frequency is too low, view (D) the CV-483 level is too low, and view (E) the CV-483 level is too high. Table 1-6.—CV-483 Speed Setting Compared to RATT Baud Rate and Printer Word-Per-Minute Settings 4. Using the transfer switchboard, you may now connect the CV-483(s) to a teleprinter or TESS HF RATT input and switch the CV-483 function switch to the "single" setting. If the printer appears to be printing garbled letters and numbers, switch the "polarity" switch to the "reverse" position. If still printing garble, adjust the "speed" switch to "slow" and adjust the printer Words Per Minute (WPM) or Baud rate setting. Baud is the rate of modulation of a transmitted signal. The words-per-minute figure is an approximation based on the relationship that one word is six-unit characters of information. Baud rate times 1.35 is the approximate WPM rate. The CV-483 speed is related to transmission baud rates and WPM rates, as shown in table 1-6. SHIPBOARD TELEPRINTERS Observers in shipboard meteorological offices equipped with the TESS (3) or later versions of TESS may direct HP RATT signals into the TESS system for automatic sorting, storage, selected recall and display, or printing of alphanumeric information. IMOSS can also be used to copy RATT data. On ships not equipped with TESS or IMOSS, the incoming information must be directed to a printer. Currently, there are two basic types of shipboard teleprinters in use: the Teletype Corporation Model 28 (several different versions) and the Navy Standard Teleprinter (NST), the AN/UGC- 143A(V). Model 28 Teleprinter The Teletype Corporation Model 28 teleprinter is a family of reliable low-speed teleprinters. Some versions are not equipped with a keyboard, and are known as receive-only (RO) teleprinters. Other versions have a keyboard and are known as Keyboard Send-Receive (KSR) teleprinters. In one version or another, Model 28 printers may still be found in shipboard meteorological offices. Some of the basic versions of the Model 28 are the TT-48/UG floor- mounted KSR teleprinter (fig. l-28), the TT-69/UG tabletop KSR teleprinter (fig. l-29), the AN/UGC-20 compact KSR teleprinter (fig. l-30), and the AN/UGC- 25 compact RO teleprinter (fig. 1-31). 1-42