A mobile data terminal is a device that helps you to connect to the internet when you're away from your home or office. It's like a mini computer that you can carry with you and use to access websites, check emails and make phone calls wherever you are. It uses 3G or 4G network technology to connect to the internet, so you need to be in an area which has good mobile coverage. With a mobile data terminal, you can stay connected, even when you're out and about!