Self-signed certificate for ePOS printers

ePOS printers are designed to work seamlessly with Point of Sale systems. Once connected, the two devices automatically share information, enabling the direct printing of tickets from the POS system to the ePOS printer.


These Epson ePOS printers are compatible with CoquiAPPs:

  • TM-H6000IV-DT (Receipt printer only)

  • TM-T70II-DT

  • TM-T88V-DT

  • TM-L90-i

  • TM-T20II-i

  • TM-T70-i

  • TM-T82II-i

  • TM-T83II-i

  • TM-T88V-i

  • TM-U220-i

  • TM-m10

  • TM-m30

  • TM-P20 (Wi-Fi® model)

  • TM-P60II (Receipt: Wi-Fi® model)

  • TM-P60II (Peeler: Wi-Fi® model)

  • TM-P80 (Wi-Fi® model)

To work with CoquiAPPs, some models that can be used without an IoT box may require the HTTPS protocol to establish a secure connection between the browser and the printer. However, trying to reach the printer’s IP address using HTTPS leads to a warning page on most web browsers.

warning page about the connection privacy on Google Chrome

Warning page on Google Chrome, Windows 10

In that case, you can temporarily force the connection by clicking Advanced and Proceed to [IP address] (unsafe). Doing so allows you to reach the page in HTTPS and use the ePOS printer in CoquiAPPs as long as the browser window stays open.


The previous instructions apply to Google Chrome but are similar to other browsers.


The connection is lost after closing the browser window. Therefore, this method should only be used as a workaround or as a pre-requisite for the following instructions.

Generate, export, and import self-signed certificates

For a long-term solution, you must generate a self-signed certificate. Then, export and import it into your browser.


Generating an SSL certificate should only be done once. If you create another certificate, devices using the previous one will lose HTTPS access.

After forcing the connection, sign in using your printer credentials to access the ePOS printer settings. To sign in, enter epson in the ID field and your printer serial number in the Password field.

Click Certificate List in the Authentication section, and click create to generate a new Self-Signed Certificate. The Common Name should be automatically filled out. If not, fill it in with the printer IP address number. Select the years the certificate will be valid in the Validity Period field, click Create, and Reset or manually restart the printer.

The self-signed certificate is generated. Reload the page and click SSL/TLS in the Security section to ensure Selfsigned Certificate is correctly selected in the Server Certificate section.


  • If you need to export SSL certificates from an operating system or web browser that has not been mentioned, search for export SSL certificate + the name of your browser or operating system in your preferred search engine.

  • Similarly, to import SSL certificates from an unmentioned OS or browser, search for import SSL certificate root authority + the name of your browser or operating system in your preferred search engine.

Check if the certificate was imported correctly

To confirm your printer’s connection is secure, connect to its IP address using HTTPS. For example, navigate to in your browser. If the SSL certificate has been applied correctly, you should no longer see a warning page, and the address bar should display a padlock icon, indicating that the connection is secure.