broadcasting, film studios, theme parks and telecommunications. It is a highly vertically integrated company, producing, retailing and delivering content to its many subscribers. Comcast entered the broadband telecommunications market as an ISP using its cable connections. Comcast and other cable TV operators are in a strong position as they have a fixed-line medium entering or passing many households in the United States. In this way Comcast competes in the same field as telephone operators which connect to homes with twisted copper wires. The development of DOCSIS standard 3.1 theoretically enables Comcast to offer broadband service at the gigabits per second transmission rate. This is a highly competitive rate and can protect Comcast from competition from optical fibre-based service providers such as Verizon FiOS and Google Fibre. The physical cable connection has afforded Comcast and other operators a golden business opportunity. Comcast's highly vertically integrated business affords it great competitive advantage. However, it is also risky from a policy point of view. Comcast has been accused of slow- ing video content from its competitors such as Netflix. This has given rise to a long policy discussion on net neutrality [15]. A structural separation of the company across the content delivery function may be unlikely, but a firmer competitive parity may be enforced. Case Study Questions How did cable TV operators first enter the ISP market? What were their subsequent moves? What are Comcast's strengths and competitive advantages? How do you see a competitor to Comcast emerging? Compare the competitive landscape in the United States with Australia which has a relatively small cable subscriber base. Optical Fibre Systems Information transmission using light signals is perhaps the most ancient form of telecommunica- tions. A more modern form of light communications was studied by Alexander Graham Bell and he invented the photophone, where voice signals were sent using a light beam. The limitation of this and o