How can I read the serial port continuously and trigger a third party device based on what is read?

Hello,

I have configured my microcontroller to output a "ping" onto the serial port COM3 whenever it encounters a TTL. I would now like to have MATLAB read that "ping" whenever it occurs. When MATLAB recognizes this "ping" I want MATLAB to trigger a third party device that is connected to the laptop via an ethernet connection.

Can anyone throw some light on how this can be accomplished?

Thank you.

P.S: I am trying along the following lines but getting MATLAB to continuously read the "ping" is becoming a little tricky.

clear all
close all
clc
s = serial('COM3','BaudRate',9600,'Terminator','CR/LF');
fopen(s)
A = fscanf(s);
while j < 1000
    if (strcmp(A,'Ping'))
        x = 0:0.1:pi;
        y = square(x);
        plot(y);
        drawnow;
    end
    j = j + 1;
end
fclose(s)
delete(s)
clear s

[Aditya]

Correction: The fscanf statement is inside the loop. But that did not help either.