Link Protocol and Interface Control
In addition to encoding data from the CDS
computer, the DTS generates and recognizes protocol
data that controls the type and number of link
transmissions. These protocol words include codes
indicating the start of transmission, the end of
transmission, and the address of the next unit to
transmit.
The interface with the CDS computer is under the
control of the DTS. The DTS signals the CDS
computer when it has input data or when it wants
output data through the use of external interrupts.
These interrupts include the prepare-to-transmit,
prepare-to-receive, and end-of-receive interrupts.
DTS CONTROLS AND INDICATORS
Many parameters that affect the operation of the
DTS are under the operator’s control, whether the
station is operating as a picket or as the net control
station. Both the operator and the technician must be
familiar with the various controls and indicators
associated with the DTS. The AN/USQ-59 uses
several control panels that are usually mounted next to
the operator’s display console. These panels enable
the operator and the technician to control and monitor
the net operation.
The control panels include a Mode Control panel,
a TADIL A Control panel, and an Address Selection
Indicator panel. Although the AN/USQ-59 control
panels are used here to show the controls and
indicators of a Link-11 DTS, other data terminal sets
have similar controls. The functions controlled by the
AN/USQ-59 control panels are software controlled
on newer data terminal sets. On these data terminal
sets, the entries an made via the computer control
console or the display console.
DTS Mode Control Panel
The DTS mode control panel controls and
indicators are shown in figure 4-15. The following is
a summary of how the controls affect the operation of
the link and what the indicators mean.
TRANSMIT MODE INDICATOR —lights
when the DTS is in the transmit mode.
RECEIVE MODE INDICATOR —lights when
the DTS is in the receive mode.
SUMMARY FAULT INDICATOR —Lights
when a fault in the DTS is detected while in the
OPERATE mode. There are 27 performance monitor
fault-sensing circuits in the data converter (modem) of
the DTS. During the OPERATE mode, 14 of these
sensors can cause a summary fault. The fault-sensing
circuits monitor areas such as various power supplies,
signal quality, preamble presence, timing, and audio
signal quality. When the DTS is in SELF TEST, the
summary fault lamp is lighted when a fault is isolated
to a function defined by switch positions on the fault
isolation control and built-in tests routines.
LAMP TEST BUTTON —causes all indicators
on the mode control panel, the TADIL A control
panel, and the address control unit to light.
FAULT MONITOR/RESET SWITCH —In the
MONITOR position, this switch allows the fault-
sensing function of the DTS to operate normally and
provide a fault summary signal to the DTS control. In
placed in the RESET position, the fault-sensing
circuits of the DTS are reset. The SUMMARY
FAULT lamp is turned off when the fault-sensing
circuits are reset.
I N T E R N A L 1 0 0 - K H Z / E X T E R N A L
SWITCH —Allows for the selection of the internal or
external 100-KHz frequency standard.
D O P P L E R C O R R O N / C O R R O F F
SWITCH —Enables the DTS Doppler correction
when placed in the CORR ON position.
FULL-DUPLEX/HALF-DUPLEXSWITCH —
In the FULL-DUPLEX position, this switch enables
full-duplex operation of the data converter and the
computer I/O adapter. It also enables loop back
processing of the transmit sidetone data for input to
the computer. In the HALF-DUPLEX position, the
DTS operates in the half-duplex mode and the
transmit sidetone is disabled from being processed
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