WJ-8711A DIGITAL HF RECEIVER
CSMA REMOTE CONTROL
5-3
The following receiver parameters are controllable via the CSMA interface:
•
local control, remote control, or remote control with local lockout,
•
tuned frequency,
•
BFO frequency,
•
detection mode,
•
IF bandwidth,
•
gain mode,
•
manual gain, and
•
RF input path.
This section of the manual contains information necessary to enable an operator to control and
monitor the above receiver parameters from an external controller on the CSMA interface. Details on how to
properly format and transmit remote messages and how to read responses from the receiver are provided.
Before attempting to operate the receiver remotely, it is recommended that the operator
become familiar with the operation and capabilities of the receiver by viewing the information provided in
Section III
of this manual. It is also recommended that the operator become familiar with the operation of the
controller by viewing its literature.
5.4
ELECTRICAL REQUIREMENTS OF THE INTERFACE
The CSMA interface is implemented on a mini-phones jack (A2J2) located on the rear panel,
labeled CSMA. The sleeve of this connector is connected to chassis to ground. The center conductor carries
the bidirectional serial data. For proper communications on the interface, a logic HIGH input should be +2
volts minimum. A logic LOW input should be +0.7 volts maximum. These logic levels are compatible with
standard TTL and 5 volt CMOS logic drivers. With appropriate level shifting circuitry, any computer
equipped with an RS-232C interface port can be used to control the WJ-8711A via its CSMA interface. To
reduce the adverse effects of reflections on the line, resistive terminations are recommended on each end of
the interface cable. The DC bias introduced by the terminations must 2.5 volts. A single resistor at
each end of the cable, connected between a clean +3 to +5 volt supply and the data line, is usually adequate.
Be sure that all devices connected to the CSMA interface have sufficient drive capability to transmit data onto
the line. The WJ-8711A CSMA port can sink up to 100 mA at a logic low output voltage of +0.7 volts.
Courtesy of http://BlackRadios.terryo.org
Summary of Contents for WJ-8711A
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Page 19: ...1 i SECTION I GENERAL DESCRIPTION Courtesy of http BlackRadios terryo org...
Page 33: ...2 i SECTION II INSTALLATION Courtesy of http BlackRadios terryo org...
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Page 47: ...3 i SECTION III LOCAL OPERATION Courtesy of http BlackRadios terryo org...
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Page 93: ...4 i SECTION IV RS 232 REMOTE OPERATION Courtesy of http BlackRadios terryo org...
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Page 123: ...5 i SECTION V CSMA REMOTE CONTROL Courtesy of http BlackRadios terryo org...
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Page 143: ...6 i SECTION VI CIRCUIT DESCRIPTION Courtesy of http BlackRadios terryo org...
Page 157: ...7 i SECTION VII MAINTENANCE Courtesy of http BlackRadios terryo org...
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Page 189: ...8 i SECTION VIII REPLACEMENT PARTS LIST Courtesy of http BlackRadios terryo org...
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Page 241: ...FP i FOLDOUTS Courtesy of http BlackRadios terryo org...
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