A modular device system is provided having a base portable electronic communication device. The base portable electronic communication device has a display side and a reverse side, and one or more antennas being located along one or more of the device edges. A ground element on the reverse side of the housing is adjacent to the antennas and is grounded to the chassis. A multi-pin connector array on the same side is located adjacent to the ground element and the ground element lies between the connector array and the antennas. The connector array includes multiple pins supporting multiple data speeds, and the high speed data pins are located closer to the array center than the low speed data pins. The array is configured and located to electrically connect to a mating array on a module device when the module device is mated to the base portable electronic communication device.