Honeywell International Inc. RTA-50D Manuale Utente
MAINTENANCE MANUAL
965-1696
(3)
The VDR uses a low insertion force, Size 1 shell ARINC 600 rear panel connector with two
inserts. The middle insert is used for aircraft interconnections and the bottom insert is used for
input power and coaxial antenna connectors. The keying pins are set to index pin code 04.
inserts. The middle insert is used for aircraft interconnections and the bottom insert is used for
input power and coaxial antenna connectors. The keying pins are set to index pin code 04.
(4)
Forced air cooling, in accordance with ARINC Specification 600, is required for cooling the
VDR.
VDR.
(5)
Three front panel LEDs provides visual indication of real-time BITE status as follows:
• Internal fault status monitoring
• External controller status
• External antenna status.
(6)
One front panel push-button switch allows activation of manual self-test.
(7)
The VDR is partitioned into five subassemblies as follows:
• Front panel module
• Main processor module
• Power supply module
• Rear interconnect module
• RF module.
B.
Other Components in the System (Subtask 23-20-59-870-011-A01)
(1)
Other VDR system components are not supplied by Honeywell. Information on these units
must be obtained from their respective manufacturers.
must be obtained from their respective manufacturers.
5.
Operation (TASK 23-20-59-870-805-A01)
A.
Voice Mode (Subtask 23-20-59-870-012-A01)
(1)
In voice mode, the RTA-50D VDR supports simplex PTT communications in any of the
760 channels with 25-kHz spacing or 2,280 channels with 8.33-kHz spacing in the 118
to 136.975-MHz range.
760 channels with 25-kHz spacing or 2,280 channels with 8.33-kHz spacing in the 118
to 136.975-MHz range.
(2)
DSB-AM is used for voice communications where the voice audio from the microphone
modulates the VHF carrier frequency. The spectrum required for this type of modulation is less
than 7 kHz. When operating in a 25-kHz channel, the excess bandwidth of the channel is used
as a guard band to reduce emissions into adjacent channels.
modulates the VHF carrier frequency. The spectrum required for this type of modulation is less
than 7 kHz. When operating in a 25-kHz channel, the excess bandwidth of the channel is used
as a guard band to reduce emissions into adjacent channels.
(3)
Voice channel selection is controlled from the flight deck by a radio tuning panel. In installations
where a radio can be used in either voice or data mode, voice and data can be set from the
flight deck by the radio tuning panel.
where a radio can be used in either voice or data mode, voice and data can be set from the
flight deck by the radio tuning panel.
B.
Mode 0 Data (Subtask 23-20-59-870-013-A01)
(1)
Mode 0 and Mode A support data link communications that use protocols now called POA.
POA uses ASCII character-oriented message formats and protocols to ensure end-to-end
error-free delivery of messages. The difference between these two modes is the interface to
the source and destination of the POA messages.
POA uses ASCII character-oriented message formats and protocols to ensure end-to-end
error-free delivery of messages. The difference between these two modes is the interface to
the source and destination of the POA messages.
(2)
Mode 0 connects to a legacy ARINC 724 or 724B ACARS MU or CMU through an analog
audio interface. Data is transmitted between the MU/CMU and VDR units at a rate of 2,400 bits
each second by MSK modulated audio signals. The MSK audio modem is in the MU or CMU.
The MSK audio signal produced by the modem is a 1,200 or 2,400-Hz tone that indicates if the
polarity of the transmitted data bit is the same as the previous bit or is different.
audio interface. Data is transmitted between the MU/CMU and VDR units at a rate of 2,400 bits
each second by MSK modulated audio signals. The MSK audio modem is in the MU or CMU.
The MSK audio signal produced by the modem is a 1,200 or 2,400-Hz tone that indicates if the
polarity of the transmitted data bit is the same as the previous bit or is different.
EFFECTIVITY
ALL
23-20-59
Page 15
1 Mar 2011
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