Our company uses a custom GSM gateway in the United States to complete wireless cellular functions such as receiving SMS. The device is made by Ejointech from China and is model number MoIP 64/512 and does SMS only (receiving).

We are facing an issue where some text messages sent to our devices randomly go missing. To verify this we’ve created a standalone node.js app that uses the Twilio API to activate SIM cards on 64 ports at a time, it then send a SMS message to each, waits for 60 seconds, tallies up what was received and not. Then it activates the next 64 slots( SIM cards) and repeats until all 8 slots are done. On every slot’s test some SMS go missing and are not recovered. The slots (SIM’s) that lose them are fine, as in the next test the SMS messages get delivered properly.

*The Twilio sent SMS logs show that the message was sometimes not delivered, which we suspect means that the SIM card never authenticated to the cell tower even though our module’s say otherwise.

We’re looking for an expert in this field to debug the issue, explain what exactly is causing it, and fix it. We expect to be able to receive 100% of messages: both when they are sent to an active port, and when they are sent to an inactive port that gets activated later on.

As you may already know, the gateway is comprised of Quectel modules (modems) clustered together on 1 logic board so that multiple phone lines can do different things at once.

We’re seeking someone familiar with these technologies to access our device and solve this issue. The candidate we hire should be very familiar with AT commands and how the Quectel EC-25 module operates.

We’re offering $5,000 to anyone who can fix this for us. We will provide you with direct access to the gateway.

Budget: $5,000

Posted On: March 04, 2024 09:03 UTC
Category: Firmware Development
Skills:JavaScript, Embedded Linux, Wireless Communication, Firmware, Electronics

Country: United States

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