An SMS gateway is a way to end a text message with or without using a mobile phone. It is mainly used to send SMS text messages from the website or applications to mobile subscribers for alert notifications. There are different ways to send SMS to a mobile phone, either via direct operator SMPP connections, aggregators, operators’ email gateway, GSM modem, and SMS gateway provider, which are basically level aggregators.
The best option is to use one of the SMS gateway providers to send and receive messages. It depends on the region you are working in; few providers provide international SMS, and some only offer the local country. It all depends on what you need, so search the web, and you will find a number of them.
SMS gateway is a software that lets you to send, receive SMS for application. It is analogous to connecting a modem to your computer and connecting it to your ISP (in the old days). If you are thinking of sending and receiving SMS from your application, there are basically some ways to do it, depending on the volume and the cost.
Use of an SMS gateway and a GSM modem
The GSM modem is basically a cell phone. You then connect this modem to your computer, either serial or USB. We have only worked with serial. You now need to configure the SMS gateway you are using, for example, what port, speed, etc. Once configured, you can now use it to send SMS. See this. This is very profitable but not very scalable. We have tested it, and we can only send 3 SMS per minute.
A second method is to use an SMS provider (do a Google search). Just subscribe to the service. They get some documents or a library to let you connect to their servers, and they will do the sending and receiving for you. To receive, the provider will provide you with a number for each country in which it has a presence.