105SL Communicating to printer via serial port connection

Article ID: 86103329



This solution is useful for

  • Serial port connections
  • Setting serial port parameters
  • Serial cabling and pin out requirements
  • Diagnosing data received by the printer

Symptoms resolved by this solution include 

  • Data light does not flash when print job is sent
  • Data light flashes but does not print
  • Printing garbage, skips print, and random misprints
  • Printing slow, may have long pauses between prints


Applies To

105SL Printer and serial port communications


The 105SL comes standard with an RS 232 9 pin interface for serial communications. This is a DTE port and if connecting to a PC Serial Interface requires a NULL MODEM cable. To ensure the printer is properly communicating to the host equipment it requires the correct baud rate , data and stop bits, parity, and handshaking. Default settings are 9600 baud, 8 data bits, 1 stop bit, no parity, and XON/XOFF. PROTOCOL Should be set to NONE.

Serial port parameters information details Read More>>

Configuring the Serial Communications Parameters Read More>>

Viewing the printer parameters Read More>>

Testing Communications

You can use the Zebra Setup Utility to verify communications by sending commands via this application test features or by sending ZPL commands via the communications window. Read More>>

You could also copy a ZPL format to the comm port. Make sure you have a complete format so the printer will respond. Read More>>


Troubleshooting Problems

Problem Solution
Printer does not respond to label requests

- Are you sending ZPL programming commands? The printer will not respond if you are not sending the printer command language. Read More>>

- Use the printer hex dump or communications diagnostics to verify you are sending ZPL to the printer Read More>>

- Make sure the printer PROTOCOL is set to NONE Read More>>


Printer starts printing but then there are skipped labels or corrupted data.

- Check host handshake and make sure it matches the host. This is the method of flow control to prevent buffer overflow Read More>>

- Make sure the cable meet the length specifications for RS232 communications (Limit is 50ft but the shorter the better)

- Check for electrical interference and limit or remove the source



Helpful Information

ZPL Examples


+ Product Codes