787 Flight Crew Operations Manual
DO NOT USE FOR FLIGHT
Communications -
System Description
Copyright © The Boeing Company. See title page for details.
5.20.4 D615Z003-TBC
Data Mode
The data mode can be selected and deselected by pushing the frequency transfer
switch when the word DATA is displayed on the active radio line. If the selected
VHF radio is the default data radio (VHF C), then DATA is displayed in the TCP
active frequency window.
When a standby frequency is transferred to the active DATA window, DATA is
now displayed in the standby window. If a new frequency is selected in the
standby window when DATA is displayed, DATA is replaced by the new
frequency. Data can be returned to the standby window by stepping through the
list of standby frequencies until DATA appears.
When a VHF radio is in the data mode, it is not available for voice
communications. A VHF radio can be returned to the voice communication mode
by transferring a voice frequency into the ACTIVE frequency window.
HF Communication System
There are two independent HF communication radios, designated HF L (left) and
HF R (right). Each HF radio can be tuned by any TCP from the main HF page.
Managing HF frequencies on the TCP is identical to VHF mode operation. Up to
three pages of stored HF frequencies (24 total) can be stored in the TCP.
[Option - No auto clear of stored frequencies]
Frequencies stored during flight (HF pages 2, and 3) may be manually deleted
using the CLR key. Frequencies not manually deleted remain stored in the TCP
after flight is completed.
[Option - USB/AM]
The HF radios operate in one of two modes, upper side band (USB) or amplitude
modulation (AM). The USB/AM key on the main HF page is used to toggle
between these two modes. In addition, the HF sensitivity is controlled by the HF
sensitivity keys. Pushing the sensitivity UP or DOWN keys increment HF
sensitivity between maximum (100) and minimum (0) volume.
The audio control panels are used to control voice transmission and receiver
monitoring.
When an HF transmitter is keyed after a frequency change, the antenna tunes
while a continuous or intermittent tone may be heard through the audio system. A
tone lasting longer than 7 seconds indicates failure of the system to tune. Data is
stored in memory for the last 100 tuned frequencies. Stored frequencies may tune
quickly and a tone may not be noticeable.
Both HF radios use a common antenna. When either HF radio is transmitting, the
antenna is disconnected from the other HF radio, and it cannot be used to transmit
or receive. However, both HF radios can receive simultaneously if neither is being
used for transmitting.
February 13, 2009
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