~JD - Enable Communications Diagnostics

Overview

The ~JD command initiates diagnostic mode that produces an ASCII printout of all characters received by the printer, including ASCII characters, HEX values, and communication errors. Used for troubleshooting communication issues and protocol problems.

Syntax

~JD

Parameters

None

Description

• Enables diagnostic printout
• Shows all received data
• Includes ASCII and HEX
• Shows communication errors
• Remains active until ~JE

Examples

Enable Diagnostics

~JD

Full Diagnostic Session

~JD
[send data to diagnose]
~JE

Output Format

Prints three columns:

1. ASCII character representation
2. Hexadecimal value
3. Communication error indicators

Troubleshooting Uses

Protocol Debugging

• Verify command format
• Check character transmission
• Debug control characters

Transmission Issues

• Detect communication errors
• Verify baud rate
• Check cable integrity

Data Validation

• Verify data received
• Detect encoding issues
• Confirm format structure

Important Notes

• Consumes significant media
• Shows all received data
• Disrupt normal printing
• Always send ~JE to exit
• Not for production use

Related Commands

• ~JE - Disable Diagnostics
• ^SC - Set Communications

See Also

• Disable Diagnostics (~JE)
• Set Communications (^SC)