Carriers are the companies that own the towers an antennae that communicate with wireless devices (pagers, phones, etc).
In order for PageGate to deliver a text message to a wireless device, the message needs to be sent to the carrier. The carrier then accepts the message into their internal network and delivers it to the device. A few commonly known carriers are: Verizon, Cingular, Nextel, and Alltel.
In PageGate, a Carrier must be created for each of company you want to message.