SLC with Zebram400 Trouble

Hi, i need to program a codebar label into a zebram400 printer, im using the AWT instruction on SLC PLC 5/04, but the printer does not print anything, i can see the DATA LED flashing when i toggle the bit on the ladder for printing. i do not know what instruction use, AWT or AWA???
this the ladder what im using.

The AWT instruction sends only the bytes in a STRING element out the serial port.
The AWA instruction sends the bytes in a STRING element out the serial port, followed by the two Append Characters defined in the User configuration for the Channel 0 serial port.

Example:

AWT sends "Hello, World !"
AWA sends "Hello, World !^d^a"

Where ^d = 0x13 = Carriage Return, and ^a = 0x10 = Line Feed.

Also, ASCII instructions do not complete before the program execution moves on to the next instruction, so placing four of them that are dependent on the /DN bits of the previous one will not work behind a one-shot.

You could remove the "XIC R6:6/DN" conditions are execute them all in parallel, or move each step to its own rung.

The program as-is writes only the first string ST9:3 out the serial port (for Rung 0).

If you need to process serial data that is coming back from the Zebra printer to the SLC, you must change the serial port mode from System to User. You can use AWT and AWA instructions with the serial port in System mode, but not any of the ASCII Read or Read Line instructions.

What is the protocol of your printer, according to your program is df1. Your baud rate, bits, acknowledge, parity and stop bits must me the same on your printer and your plc.
My guess is that your printer protocol must be ascii, so you have to change your channel 0 to user mode. Again smae for baud rate, bits, parity, stop bits and acknowledge. In this case you have to use the DH-485 port on your plc to comunicate with your pc. because the plc´s serial port is busy with the printer.