Issue with SIM800L

I have a sim800L device connected directly to a serial bus on my computer. Via putty I can see I am connected to Tmobile and am in registered roaming mode (1,5). I can use another phone to send a sms to my hologram number and it will show up in the putty terminal. Even if i set the parameters (listed below) I cannot send sms messages. Any troubleshooting tips would be greatly appreciated.

+CMT: “+1814xxxxxxx”,"",“Date”





+CMGS: 26


I never get the sms on my phone.

Your code looks good. I experienced the same issue today and we’re looking into what might be causing this. There is a chance this is a module issue. But we are not sure yet.

At any rate, we highly recommend sending data through TCP instead of SMS. SMS is slow, TCP is fast. SMS costs more $ on our platform and data is extremely affordable. If you need to send SMS to another device we offer SMS-over-IP which allows you to send data through TCP to our cloud and have our cloud send an SMS on your behalf. It is fast and saves you from SMS charges.

Note: Our docs use domain but the SIM800 requires an IP. The cloudsocket IP is

Alright thanks! I plan on deploying a debugger at work that uses an arduino and simcard to connect to local data. Is there any other module you suggest instead of the 800? We already have plans to push a status page over tcp but we would like a sms component as a fail-safe. For example we could text START GEN1 to trigger a generator to start in an emergency situation.

For now I will continue to play around with the 800 in tcp mode and test out your SMS over IP using your library.

We are in a weird industry state right now with modules. Everyone is waiting for 4G Cat-NB and Cat-M1 to roll into the mainstream. That new technology is made for IoT. Until then the SIM800 module is a decent option but only offers 2G connection (we’ll be supporting 2G in the states until 2020).

Our Dash MCU might be a better solution if you want better coverage (2G+3G) and a nicer system API.