Introduction

This server allows you to integrate an ESC/POS compatible receipt printer via MQTT. It translates programs written in a DSL an received via MQTT into ESC/POS programs, and forwards these programs to a printer.

Connection to the printer

Currently only networked ESC/POS printers are supported. They are auto-discovered via network. A log message will indicate which printers were found. Discovery is done using Epsons discovery protocol which records responses to a UDP multicast packet. The printer is then identified via SNMP.

Connections to all printers are initiated on port 9100 (RAW printing port).

You also have the option to manually configure a printers network settings. To do so, specify the hostname or IP address in the MANUAL_PRINTER_HOST environment variable. You also have the option to specify the printer model for that printer in the MANUAL_PRINTER_MODEL variable.

The default fallback model (if it cannot be discovered for example) can be overriden using the DEFAULT_PRINTER_MODEL variable.

See a list of supported printer model values in the documentation of escpos-db.

Connection to MQTT

Configure the connection to your MQTT broker using the MQTT_URL variable. Example values for that may be:

mqtt://username:password@mqtt-broker/
mqtt://broker/

Printing

To print, send a program to the printers MQTT topic. A program is a newline-separated listed of commands. See the command reference for a description of all commands.

The specific topic of a printer follows the structure escpos/{printer_id}/print, where printer_id is the printers ID. Find the printers ID by checking the logs, or manual if you want to use the manual printer.

HomeAssistant

The service will create notify entities for HomeAssistant MQTT discovery. Send programs to these notify endpoints to print receipts via HomeAssistant easily. Alternatively, you can publish raw MQTT messages to the correct topics.