Which GSM gateway to choose for sending SMS (with API)?

Question

Iron

Please advise some kind of hardware GSM-gateway with the ability to send SMS from applications using the API.

Answer 1

The question also satisfies the Android application that opens the API via USB or over the network:
https://play.google.com/store/search?q=sms%20gatew...
https://play.google.com/store/ search?q=smpp
https://play.google.com/store/apps/details?id=com....