^SC - Set Communications

Overview

The ^SC command allows you to change the serial communications parameters the printer uses for RS-232 communication. This includes baud rate, data bits, parity, stop bits, handshaking protocol, and Zebra-specific protocol settings. These settings must match the configuration of the host computer or device sending data to the printer.

Syntax

^SCa,b,c,d,e,f

Parameters

• a = Baud rate (110-19200 bits per second)
• b = Word length / Data bits (7 or 8)
• c = Parity (N=None, E=Even, O=Odd)
• d = Stop bits (1 or 2)
• e = Handshake protocol (X=XON/XOFF, D=DTR/DSR)
• f = Zebra protocol (N=None, Z=Zebra, A=Ack/Nak, Y=Zebra v20.5.2+)

Parameter Details

Baud Rate (a)

Common values: 110, 300, 600, 1200, 2400, 4800, 9600, 19200

• 9600 = Most common
• 19200 = High speed
• Lower rates = More reliable for long cables

Word Length (b)

• 7 = 7 data bits (legacy)
• 8 = 8 data bits (standard, default)

Parity (c)

• N = None (no parity checking)
• E = Even parity (even number of 1 bits)
• O = Odd parity (odd number of 1 bits)

Stop Bits (d)

• 1 = One stop bit (standard)
• 2 = Two stop bits (legacy)

Handshake Protocol (e)

• X = XON/XOFF - Software handshaking

  • Printer sends Ctrl-S (XOFF) when buffer full
  • Printer sends Ctrl-Q (XON) when ready for more data
  • Useful for slower connections

• D = DTR/DSR - Hardware handshaking

  • Uses hardware signals on serial port
  • More reliable than software handshaking
  • Requires proper cable configuration

Zebra Protocol (f)

• N = None - No special protocol
• Z = Zebra - Zebra-specific protocol enabled
• A = Ack/Nak - Acknowledge/Negative-Acknowledge protocol
• Y = Zebra (v20.5.2+) - Alternative to Z

Description

• Configures RS-232 serial port communication
• Critical for printer-host communication
• Must match host computer settings exactly
• Settings persist across power cycles
• Allows partial updates without resetting all parameters

Usage Notes

• If you do not specify a new setting for a parameter, it remains unchanged
• Empty parameters (,,) leave those settings unchanged
• All parameters must match host computer configuration
• Incorrect settings result in communication failures
• Most common configuration: 9600,8,N,1,X,N
• Parameter f updated in v20.5.2 to accept Y for Zebra protocol

Examples

Standard Configuration (Most Common)

^XA
^SC9600,8,N,1,X,N
^FO50,50^A0N,30,30^FDStandard Setup^FS
^XZ

Sets: 9600 baud, 8 data bits, no parity, 1 stop bit, XON/XOFF, no Zebra protocol.

High-Speed Configuration

^XA
^SC19200,8,N,1,D,Z
^FO50,50^A0N,30,30^FDHigh Speed Setup^FS
^XZ

Sets: 19200 baud, 8 data bits, no parity, 1 stop bit, DTR/DSR, Zebra protocol.

Enable Zebra Protocol Only

^XA
^SC,,,,,Z
^FO50,50^A0N,30,30^FDEnable Zebra Protocol^FS
^XZ

Changes only Zebra protocol setting to Z, leaving all other parameters unchanged.

Change Baud Rate Only

^XA
^SC4800
^FO50,50^A0N,30,30^FDLower Baud Rate^FS
^XZ

Changes baud rate to 4800, keeps all other settings.

Acknowledge Protocol

^XA
^SC9600,8,N,1,X,A
^FO50,50^A0N,30,30^FDAck/Nak Protocol^FS
^XZ

Sets Ack/Nak protocol for error checking.

Common Configurations

Handshaking Comparison

Troubleshooting

No Communication

• Verify baud rate matches host
• Check data bits (usually 8)
• Verify parity setting
• Check handshaking protocol
• Verify physical serial cable

Garbled Characters

• Baud rate mismatch
• Parity setting incorrect
• Data bits setting wrong
• Interference on serial line

Slow Communication

• Consider higher baud rate (9600 → 19200)
• Verify handshaking is working
• Check cable quality
• Consider DTR/DSR over XON/XOFF

Related Commands

• ^KL - Define Language
• ^KP - Define Password
• ^JU - Configuration Update

See Also

• Define Password (^KP)
• Define Language (^KL)