Question about SMS charges | 7-Eleven Rates and Plans | Consumer forum

I recently installed a GSM security system which is programmed via telephone by typing in a certain code or can also be programmed via SMS to enter various programming features. When it accepts the command it sends a SMS message to my cell phone letting me know which code was accepted. Is that a 1 minute call charge?

Are the replied SMS charged as if it were a 1 minute call? Or are these charges different not having a data plan.

In 2 days about $ 14.00 were used up on the Security system Sim number.

Can someone enlighten these charges up me please? Outgoing and incoming.

Thanks