The electronic module controls the functional
operations of the NST and provides temporary storage
of all transmitted and received information. It contains
a message buffer memory, message segmentation logic,
message routing logic, communication port, crypto
port, and power supply. The buffer compensates for
varying baud rates and holds incoming traffic until the
entire message has been received, and then sends it to
the printer.
The printer module contains the printer mechanism,
printer electronics, printer buffer, status indicator,
system setup switches, and power supply. All received
or transmitted information may be automatically
printed. The operator can interrupt the printing mode
without losing incoming message traffic to print
directory information or internal systems test results. A
dot-matrix print mechanism is capable of printing line
lengths up to 80 characters at a speed of 120 characters
per second (1200 WPM). (Until all Model 28
teleprinters have been replaced ashore and afloat, only
69 characters are allowed in a single message line.)
Operator-selected, single- or double-line spacing
modes are available. The printer uses either friction-
feed nonperforated or tractor-feed perforated fan-fold
paper. It is capable of accommodating single-ply paper
or five-ply paper.
The keyboard module contains the basic
complement of keys needed to send characters, release
tape reader input, and perform tape editing. Another
variation of the keyboard module includes a one-line
(80-character) LCD display and special function keys
that help the operator in message preparation and
correction (fig. 1-35). The gray shaded keys are
command or edit functions. Many of the remaining keys
contain message functions, accessed by holding down
the "shift" key as the function is depressed. Notice that
the keyboard contains carriage return (CR), line feed,
letters (LTRS), and figures (FIGS) keys, similar to the
older Model 28 keyboards.
The bulk storage module contains the tape drive,
drive electronics, message file logic, bulk storage
buffer, function control switches, and power supply. It
automatically stores all received and transmitted
messages on a removable data cartridge. This module
maintains an archive directory listing (table ofcontents)
of all messages stored. The operator can have the table
of contents printed or displayed on the keyboard
module screen. The table of contents lists the messages
in date-time group order and includes the originator,
NAVCOMPARS processing sequence number (PSN),
and an access number by which the operator can recall
the message from storage. A data cartridge tape can
store up to 1,344 messages of 2,000 characters each.
Figure 1-35.—AN/UGC-143A(V)4 ASR keyboard.
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