The DR5 & DR4 mobile devices (default configuration) contains a cellular radio and 2 SIM card slots that can be used to access the cellular network. Wasp does not support this functionality, but customers are welcome to use it. The devices will work with SIM cards for GSM and HSPA+ technologies, which includes AT&T, T-Mobile, Cricket, Boost etc. They will NOT work with Verizon's network.
Other mobile devices sold by Wasp do not contain any radio for connecting a cellular phone network, so they are not capable of acting as a cell phone.
This is not affected by whether a device contains a SIM card slot (including models HC1, WDT60, and WDT90) or not (including model DR2).