VIEWSONIC VPAD10 VS13790 - Manual (Page 17)

7 ViewSonic VPAD10
 Vents
Dissipate heat and keep your VPAD10 at an optimal temperature.
 3G SIM card slot
Insert a 3G SIM card (can not support PnP), then you can connect to 3G network.
(For more information, please contact local Telecom Operators.)
The configurations may vary depending on the model number. Check the actual model for specifics.