If data transmission doesn't work, the possible reasons are as follows: · No 4G antenna connected; · D SIM card inserted; · The PC configuration is incorrect. For example, the gateway router does not do port mapping. · DVR: The wireless setting part of the setting menu is incorrectly set. For example, the wireless dialing is not turned on, the 4G protocol settings are incorrect, the access point settings are not equal; the central serve part of the setting menu is incorrectly set. For example, the center IP setting is incorrect.