Coordinate Data Transfer Control
The coordinate data transfer control assembly
enables the connection of each of the digital-to-digital
converters (DDC) to one of two different computers.
The control panel for the coordinate data transfer
control assembly is shown in figure 4-5.
COMPUTER SELECT provides switching, such that
DDC A is connected to computer 1 and DDC B is
connected to computer 2 or vice versa. Either of the
two DDCs maybe connected to its monitor test panel
for off-line testing. The DDC output options are the
CDS (old NTDS) radio set, the CAINS system, or the
The digital-to-digital converter assembly provides
system timing, converts parallel data from the CDS
computer into serial data for transmission by the UHF
radio set, and converts serial data received from the
radio set into parallel data for input to the CDS
computer. The DDC is the heart of the data terminal
Monitor Test Panel
The monitor test panel provides the technician
with a means to monitor Link-4A operations and off-
line testing capabilities. There is one monitor test
panel for each DDC.
The pulse amplifiers provide level and signal
conversion functions to allow the AN/SSW- 1D/E data
terminal set to drive the serial output for the UHF
radio set and the deck edge outlet boxes for CAINS.
The communications switchboard interconnects
the AN/SSW-1() to the UHF radio sets.
communications switchboard is similar to the Link-11
switchboard described in chapter 2 of this manual.
LINK MONITOR SYSTEM (LMS-4)
The LMS-4 provides stand-alone Link-4A
monitor and readiness check capabilities.
operation is similar to that of the LMS-11 covered in
the previous chapter. The monitor function listens
passively to the Link-4A communications between the
control station and the controlled aircraft. Signal
analysis and test message validity are performed on
the data. The readiness check function tests the
readiness of the control station to conduct live two-
way Link-4A operations.
transmitted by the control station are monitored and
the LMS-4 generates the reply messages required to
maintain two-way communications.
This chapter introduced you to the Link-4A
communications system. The following information
highlights some of the important points you should
LINK-4A CDS SYSTEM The Link-4A CDS
system provides one-way or two-way communication
between the controlling station and up to 100 aircraft.
Link-4A messages contain flight commands and
tactical information for the aircrafts pilot. The four
modes of operation for the Link-4A CDS system are
intercept vectoring, air traffic control, the automatic
carrier landing system, and precision course direction.
Intercept vectoring mode is used to guide an
aircraft to an assigned target. Air traffic control mode
is used to control the aircraft in a carriers landing
traffic pattern. The automatic carrier landing system
uses the carriers precision approach radars to land an
aircraft on the flight deck automatically. Precision
course direction mode provides very accurate control
of an aircrafts flight path and is used for the remote
guidance of bombers, reconnaissance aircraft, and
C A R R I E R A I R C R A F T
NAVIGATIONAL SYSTEMS (CAINS) The
CAINS system is used to load way-point and
alignment data into the navigation computer of an