A timeout occurred before the Terminator was reached in matlab serial communication

Hello,

I tried to estrablish serial commnunication between two computers using the following command wriiten below but while executing i am getting following error A timeout occurred before the Terminator was reached in matlab serial communication

s = serial('COM1'); set(s,'BaudRate',4800); fopen(s); fprintf(s,'*IDN?') out = fscanf(s); fclose(s) delete(s) clear s

Let me know how to resolve it