iXBlue OCEANO RT2500S Series, Руководство пользователя, Страница: 59 / 66

OCEANO RT2500S/RT5000S Series – User Guide
Appendices
A. E
XCHANGES BETWEEN
MMI B
ALI AND
RT8
X
1 T
RANSPONDERS
The communications between the RT8x1 acoustic transponders and the man-machine
interface are achieved through a bi-directional serial link, through messages whose format
is inspired from standard NMEA 0183.
Data transmission is achieved upon request from the transmitter, or upon request from the
receiver. The essential phases are summarized hereafter.
Each message consists of a maximum of 79 ASCII printable characters (codes $20
through $7F) placed between the line start and line end characters, transmitted in the
following format:
1 start bit,
8 data bits without parity (MSB = 0),
1 stop bit,
fixed rate of 4 800 bauds.
The following characters are reserved as they have a particular meaning:
$ Message start
, Field separator
Checksum field separator
<CR><LF> Message end ($0D$0A)
The general frame of a message is as follows:
MU–RT8x1–AN–001 Ed. M – September 2013 49