RS-232 REMOTE OPERATION
WJ-8711A DIGITAL HF RECEIVER
4-26
4.8
RS-232 COMMUNICATIONS PROTOCOL
The communications protocol for the WJ-8711A implements both ENQ/ACK
(ENQuire/ACKnowledge) and XON/XOFF (ctl Q/ctl S) software handshakes. The ENQ/ACK format,
typically referred to as "transmitter protocol", allows the operator to send an "ENQ" character to the WJ-
8711A when an acknowledge is required. The receiver then responds with the ACK/NAK
(ACKnowledge/Not AcKnowledge) character indicating the validity of the data received in the input buffer
and the fact the unit has completed all current data through to the last received terminator. The XON/XOFF
format supports both transmit and receive communications. This format, typically referred to as "receiver
protocol", allows transmission based on the availability of buffer space (refer to
paragraph 4.8.3
).
Table 4-7
lists the supported communications control commands for RS-232 remote
operation. The following paragraphs provide more details on the ENQ/ACK and XON/XOFF protocol, and
buffer control.
Table 4-7. Supported RS-232C Communications Control Commands
HEX
ASCII
Receive
Transmit
Function
11
13
DC
DC3
x
x
x
x
XON, allow data transmission
XOFF, disallow data transmission
05
06
15
ENQ
ACK
NAK
x
x
x
Enquire, request acknowledge
Acknowledged, data received
Not acknowledged, data communications
error
0A
0D
LF
CR
x
x
x
x
Line feed, start processing input buffer
Carriage return, no action
4.8.1
XON/XOFF PROTOCOL
The XON/XOFF communications protocol is always active in the WJ-8711A. In the event the
buffer has room for less than 16 additional characters the unit will output an XOFF character. When the unit
empties its input buffer, it issues an XON character. The user must stop sending data within 15 characters
after receiving the XOFF character. On each character that is received while the buffer is full, the unit issues
an XOFF character. The user may start sending data to the unit after receiving the XON character.
The WJ-8711A responds to the XON and XOFF commands while outputting data to the user.
If the unit receives an XOFF while sending, it stops transmitting within two characters. The unit will not
transmit any further data until an XON is received. The WJ-8711A assumes the XON condition at power-up.
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...
