Manual

June 2004 Isis® Sonar User's Manual, Volume 2
37
Pin 7 ------------------------ Request To Send ------> _______________________
Pin 8 <---------------------- Clear To Send ------------ _______________________
Pin 9 <---------------------- Ring Indicator ------------ _______________________
*Only pins 2, 3, and 5 are needed for a complete interface. All other pins are
physically connected but not used by the Isis software.
Some serial communications devices use DB-25 connectors. These may be
connected to Isis with the installation of a DB-9 to DB-25 converter or similar
cable, which may be purchased at an electrical supply shop.
The serial cable should be connected to Isis with the power OFF.
D.2 Receive Data Format
Because Isis can connect to many different navigation or telemetry systems, a
generic user-definable method has been developed to allow easy integration of
new interfaces. Isis can accept and store a wide range of navigation and
telemetry information. Although both binary and ASCII data may be received over
a serial port, use of a user-defined navigation template requires serial data to be
received in ASCII.
Note: All values transmitted over the serial port must be separated (delimited)
by a non-numeric character. Numeric characters are included in the following set:
{0123456789.-}
Here’s what happens when Isis gets data from a serial interface:
1. Isis receives a single transmission string from the serial port. This
string is terminated with any character (or characters) having an ASCII
value of less than 14. This includes carriage return and line feed (CR,
LF).
2. Isis parses the serial transmission based on the alphanumeric
combination of characters.
3. Isis assigns each number in the string to the respective field
described by the Serial Template, described next.
Appendix D: Serial Interfaces