A communication system and method are provided. In the communication system, a first electrical device has an end point which is configured to connect to a plurality of 3G dongles, wherein the 3G dongles have different IP addresses; a cloud server integrates the IP addresses to generate an integrated IP address when the cloud server detects that the first electrical device is connected to the 3G dongles; and a second electrical device transmits data packets with the first electrical device via the integrated IP address through the cloud server.