~JD (Enable Communications Diagnostics) — ZPL Command Reference

Plain English

Puts the printer into diagnostic mode where it prints all incoming data as ASCII hex on labels instead of interpreting it as ZPL. Invaluable for debugging communication issues.

When to use

When troubleshooting — you're sending data but the printer isn't doing what you expect. This shows exactly what bytes it's receiving.

Syntax

~JD

Example

~JD

Enable diagnostic mode (prints raw data as hex)

Try it in the playground View all ZPL commands