GSM Shield Call out to check line

Hi guys,

I am looking at making a small system for my job with a GSM shield to check the status of phone lines of our lifts. (Most run off a GSM module).

The idea is that I send a phone number to the Arduino, Arduino then uses the GSM shield to ring the number. As soon as there is a dial tone Arduino hangs up and sends me a confirmation that the phone line on the other end is OK (or not).

Is this possible with getVoiceCallStatus()? Ideally, the phone on the other end doesn't even ring.

Any suggestions?

Thanks guys, Erik

As soon as there is a dial tone

A what now? I thought this was a GSM phone.

You mean when you hear it ring? That's not a dial tone. Go ask grandpa what a dial tone was.

Mate, very helpful, thanks for going into technical depth. You have really grasped the purpose of a forum. The sharing of knowledge.

Yes, our lifts use dinosaur phone lines because they are reliable in case of a power drop out.
All I want to know is if it is possible to detect an active line on the other side.


Ok. I’m still confused by what you want to do. You started out talking about gsm now you say they’re land lines. What do you have? What do you want to do with it? If you’re calling those phones then you won’t hear any dial tone. That’s not what a dial tone is.

But that’s the word you used. If you mean something else then how the hell am I supposed to know? I can only know what you wrote. So I asked for clarification. If that bothers you then don’t answer this and just keep wondering. But I can’t help you if you won’t help me understand your issue.

Ok mate, I get that you can only help if I communicate my problem clearly.
I don't know what the perfect terminology is, so let me try to explain.

I want to use a GSM module on an Arduino board that is then hooked up to my pc.
This way I guess I have created a Gateway to call number from my pc.

I want to use this to call mobile numbers and landlines. Basically,
I want to check whether or not the number I am calling is active.

Is it ringing on the other side of the line, or is there copper line deactivated, cut, corroded or exploded.

We also use a GSM module that creates a landline. Please see:

I want to check if their system is still up and running, maybe the power is off the unit and so if I call it it will not be active.

Does this make sense?

Cheers bro

When you use the shield to make a call you get a response back as to whether or not it went through. All you have to do is see if it returns true or false IIRC.


Nope… Have fun. Good luck.