To represent program around a character from the RS232c port to hollow and it on the display:
Fat-marked lines with line number in the PRO mode (press MODE key )to at the display PRO appears above input and in each case with ENTER key acknowledge.

COM1 = serial RS232c interface
COM2 = SIO interface (opto-electronic interface)

Receive buffers on 2048 bytes set
10 INIT " COM1:", 2048
Deletes the display
20 CLS
All variables on zero
30 CLEARS
Transfer parameter for the serial interface
1.Parameter data transmission rate in Baud (50 to 38400)
2.Parameter word length in bits (7 or 8)
3.Parameter parity (E=even O=odd N=nothing)
4.Parameter stop elements (1 or 2
5.Parameter X-on X-off log (X=on N=off log)
6.Parameter SHIFT in/out log (S=ont N=off log)
40 SETCOM " COM1:", 9600, 8, n, 1, n, n
Defines the permitted line length (number of characters of a line to 255) and the EOL code (0=cr(asc13) 1=lf(asc10) 2=cr+lf(asc13)+(asc10))
50 PCONSOLE " COM1: ", 255,2
RXD$ gets a value of the serial INTERFACE (RS232c)
At the moment no character is available 2 times behind in vein ASCII32 = space is output.
Is a transfer error forwards becomes ASCII63 = ? and 2 times ASCII32 = space output.
60 A$=RXD$
The character on the display outputs
70 print A$
Program end
80 END

If the program were input, the MODE key press to at the display RUN appears above. Then in the display RUN input and with the ENTER key acknowledge. The program is now executed.