WJ-8711A DIGITAL HF RECEIVER
CSMA REMOTE CONTROL
5-1
SECTION V
CSMA REMOTE CONTROL
5.1
INTRODUCTION
This section provides information for controlling the WJ-8711A Digital HF Receiver via a
CSMA/CD interface. The Carrier Sense Multiple Access with Collision Detection interface (hereafter
referred to as a CSMA interface) is a media access method that allows up to 63 devices to be addressed on a
common bus interface. To transmit, a controller waits for a quiet period on the medium (that is, no other
device is transmitting) and then sends a message in byte-serial form. The controller waits for responses to
queries or for Acknowledge (ACK) or Not Acknowledge (NAK) messages before proceeding with the next
command or query. Message collisions can occur on a CSMA interface and are more likely when the system
hardware limitations are pushed beyond recommendations. The CSMA interface detects these collisions and
tries to overcome resulting communications loss. See
paragraph 5.9
for a full description of the behavior of
the interface during collision detection.
5.2
CONTROLLING MULTIPLE RECEIVERS VIA THE CSMA INTERFACE
System hardware configuration will dictate the limitations regarding the number of units
physically capable of being controlled. For best results, Signia-IDT, Inc. recommends the following:
Limit the number of bus controllers to one;
Send one command line at a time;
Wait for a response to a query or an Acknowledgment (ACK) or non-
Acknowledgment (NAK) of a command before proceeding with the next step;
Do not string commands and queries together on a single command line;
Avoid commands that do not task the receiver to return an ACK/NAK or other
response;
Limit the number of devices on the bus;
Signia-IDT, Inc. recommends the use of a ICOM CT-17 CI-V Level Converter to control
multiple receivers via their CSMA interfaces when the controller is a PC equipped with an RS-232 serial
interface. Refer to
Figure 5-1
. Signia-IDT, Inc. has successfully driven up to six receivers by adding audio
adapter jacks to extend the four outputs provided by the ICOM CT-17.
Courtesy of http://BlackRadios.terryo.org
Summary of Contents for WJ-8711A
Page 4: ...iv THIS PAGE INTENTIONALLY LEFT BLANK Courtesy of http BlackRadios terryo org...
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...
Page 34: ...2 ii THIS PAGE INTENTIONALLY LEFT BLANK Courtesy of http BlackRadios terryo org...
Page 47: ...3 i SECTION III LOCAL OPERATION Courtesy of http BlackRadios terryo org...
Page 48: ...3 ii THIS PAGE INTENTIONALLY LEFT BLANK Courtesy of http BlackRadios terryo org...
Page 93: ...4 i SECTION IV RS 232 REMOTE OPERATION Courtesy of http BlackRadios terryo org...
Page 94: ...4 ii THIS PAGE INTENTIONALLY LEFT BLANK Courtesy of http BlackRadios terryo org...
Page 123: ...5 i SECTION V CSMA REMOTE CONTROL Courtesy of http BlackRadios terryo org...
Page 124: ...5 ii THIS PAGE INTENTIONALLY LEFT BLANK Courtesy of http BlackRadios terryo org...
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...
Page 158: ...7 ii THIS PAGE INTENTIONALLY LEFT BLANK Courtesy of http BlackRadios terryo org...
Page 189: ...8 i SECTION VIII REPLACEMENT PARTS LIST Courtesy of http BlackRadios terryo org...
Page 190: ...8 ii THIS PAGE INTENTIONALLY LEFT BLANK Courtesy of http BlackRadios terryo org...
Page 241: ...FP i FOLDOUTS Courtesy of http BlackRadios terryo org...
Page 242: ...FP ii THIS PAGE INTENTIONALLY LEFT BLANK Courtesy of http BlackRadios terryo org...
