Section 11 - Beacon receiver binary protocol
05/01/97 REV H
PAGE 61
Section 11 - Beacon receiver binary protocol
11.1 Beacon receivers (8800 series and 8900 series)
11.1.1 Binary
control messages
If your differential-ready GPS receiver is compatible with the Magnavox
MX-50R radio-beacon interface protocol, a subset of this command proto-
col can be used to control the 8800 DGPS receiver. These binary control
messages consist of a function byte followed by parameter bytes.
Like NMEA 0183 control messages, binary control messages are accepted
on either the monitor or control input ports; they aren’t echoed. Any out-
put that’s generated in response to a binary control message is directed to
the RTCM SC-104 output port where it’s interspersed with the RTCM
SC-104 data bytes. (Since the bytes contain two-bit type flags, there isn’t
any interference with normal RTCM SC-104 data processing.)
Frequency select
The frequency-select command consists of the hexadecimal byte
CE
fol-
lowed by a two-byte frequency-selection code. Divide the desired tuning
frequency by 100 Hz, then encode that number into two bytes: The first
byte is hexadecimal
C0
plus the six most significant bits (
msb6
); the sec-
ond byte is
C0
plus the six least significant bits (
lsb6
). The general format
for this command is:
CE C0+
msb6 C0+lsb6
For example, tune channel 1 to 304.5 kHz:
CE EF E5
Commanding a frequency of zero returns the 8800 to its automatic mode.
For example, return the 8800 to automatic mode:
CE C0 C0
Bitrate select
An explicit bitrate for the received beacon signals must be specified when
using the binary control protocol. You may specify it either before or
after the frequency selection. Here are the hexadecimal bit-rate selection
codes:
•
D4
= select 25 bits per second (bps)
•
D5
= 50 bps
•
D6
= 100 bps
•
D7
= 200 bps
Summary of Contents for 8700
Page 2: ......
Page 10: ......
Page 16: ...Section 2 Introduction PAGE 6 05 01 97 REV H ...
Page 20: ...Section 3 Packaging PAGE 10 05 01 97 REV H ...
Page 32: ...Section 6 GPS beacon combination receivers PAGE 22 05 01 97 REV H ...
Page 46: ...Section 8 Input output configurations PAGE 36 05 01 97 REV H ...
Page 52: ...Section 9 Connector pinouts PAGE 42 05 01 97 REV H ...
Page 76: ...Section 12 8X00 engine monitor program PAGE 66 05 01 97 REV H ...
Page 78: ...Section 13 Glossary PAGE 68 05 01 97 REV H ...
Page 80: ...Section 14 Abbreviations and initialisms PAGE 70 05 01 97 REV H ...
Page 85: ...Index 05 01 97 REV H PAGE 75 ...