Here is some quick source code to control a ProXR series relay controller using Matlab. This code cycles the relay on and off and displays the return data. The bytes sent to the controller can be easily changed to send other commands to the controller. The communications baud rate is set to 115.2K Baud.
clc
clear all
close all
ncd=serial('COM3'); % assign serial port object
set(ncd, 'BaudRate', 115200); % set BaudRate to 9600
set(ncd, 'Parity', 'none'); % set Parity Bit to None
set(ncd, 'DataBits', 8); % set DataBits to 8
set(ncd, 'StopBit', 1); % set StopBit to 1
%display the properties of serial port object in MATLAB Window
disp(get(ncd,{'Type','Name','Port','BaudRate','Parity','DataBits','StopBits'}));
fopen(ncd); % Open Serial Port Object
fwrite(ncd,254); % ProXR Header Byte
fwrite(ncd,108); % Turn on Relay 1
fwrite(ncd,1); % in Relay Bank 1
disp(fread(ncd,1)); % Read Confirmation Data
disp('Relay Is On'); % Tell User Relay has Activated
pause(1); % Short Delay (not required)
fwrite(ncd,254); % ProXR Header Byte
fwrite(ncd,100); % Turn off Relay 1
fwrite(ncd,1); % in Relay Bank 1
disp(fread(ncd,1)); % Read Confirmation Data
disp('Relay Is OFF'); % Tell User Relay has Activated
fclose(ncd); % Close Serial Port Object