# ESF-IDF thru A7670 connection to free HiveMQ instance

**URL:** https://community.hivemq.com/t/esf-idf-thru-a7670-connection-to-free-hivemq-instance/2702
**Category:** HiveMQ Cloud
**Created:** [February 12, 2024, 3:57pm UTC](https://community.hivemq.com/t/esf-idf-thru-a7670-connection-to-free-hivemq-instance/2702 "2024-02-12T15:57:25Z")
**Posts on this page:** 1
**Showing post:** 10

<div class="post-metadata">

### Author: ![frarugi87](https://avatars.discourse-cdn.com/v4/letter/f/bb73d2/32.png) [@frarugi87](https://community.hivemq.com/u/frarugi87)
#### Post date: [December 22, 2024, 10:26pm UTC](https://community.hivemq.com/t/esf-idf-thru-a7670-connection-to-free-hivemq-instance/2702/10 "2024-12-22T22:26:15Z")

</div>

If you need some help with the AT commands, I just published a sum up of what I had to use to publish with the A7670:

> [@Publishing with SIMcom A7670](https://community.hivemq.com/t/publishing-with-simcom-a7670/3417):
>
> Hi all Since I lost some time to understand how the module works and I wasn’t able to find resources to have a working example (apart from arduino libraries which handle the SSL communication in software), here is the list of commands that allows me to publish on a private (serverless) HiveMQ instance with the A7670 module. First of all you need to upload the root\_ca certificate on the module: AT+CCERTDOWN="isrgrootx1.pem",1939 -----BEGIN CERTIFICATE----- MIIFazCCA1OgAwIBAgIRAIIQz7DSQONZRGPgu…

---

_[View the full topic](https://community.hivemq.com/t/esf-idf-thru-a7670-connection-to-free-hivemq-instance/2702)._