Comcast experienced a major outage involving digital television signals in the area. In Arlington Heights, the outage lasted from about 4:40 a.m. to 5:18 a.m. The Tech Outage is classified as a Level 3. Much of the Chicago area is affected by the Comcast Outage. The headend that transmits service to customers was affected by a technical problem, and the major outage was not caused by a problem with cable lines in customers' backyards, neighborhood lines, or along interior lines in residences. A cable television headend is an electronics facility used for receiving television signals for processing and distribution over the cable television system. The headend functions to receive and re-transmit video over the local cable infrastructure and a large geographic area. The headend facility usually has several large satellite dishes used to receive television signals from the television station providers via satellites.