The AT&T Unite device has a phone number and receives text messages, but there is no way to answer these messages

What none of the instructions tell you is that your temporary password is the last 4 numbers of the phone number assigned to your device.

Keep in mind that even though it is not a phone it is treated as one and you are assigned a phone number

Reception is the same as a cell phone, in fact when you create an account you get a phone number from AT&T for the device

U will not regret it