it does not decrease the amount of capacity for video. However, it is costly. Optical transceivers and receivers as well as amplifiers and set-top boxes need to be replaced or upgraded, depending on the age of the existing cabling and electronics. Optical transceivers and receivers convert signals on optical cabling to those compatible with copper cabling, and vice versa. Amplifiers strengthen signals that naturally weaken after traveling over distances, particularly on copper-based coaxial. In symmetric transmissions, which are specified in Full Duplex DOCSIS 3.1 implementations, upstream and downstream bits share the same spectrum. This is accomplished by equipment that can listen and transmit at the same time and cancel what the equipment has already "heard." Once the transmitted bits are "heard" they can be cancelled, and only changed bits are transmitted. Symmetric, full duplex transmissions use the HFC spectrum more efficiently than DOCSIS 3.0. They are spectrally efficient, enabling both upstream and downstream bits to use the full capacity of the cabling. Symmetric service is important for business customers that access cloud-based applications where more capacity than previously is needed on the uplink as well as the downlink where data is downloaded from applications such as Salesforce.com located in the cloud. Upstream www.TechnicalPDF.com capacity is also needed for residential subscribers who increasingly upload long-form, high- resolution videos to Facebook, Snapchat, YouTube, and other social networks. Competition from Streaming TV and Traditional Telephone Companies Customers that "cut the cord" or that never subscribed to cable TV or satellite TV can opt for over the air service television broadcasts beamed from towers. National broadcasters (ABC, NBC, CBS, Fox, and Spanish channels) and their local affiliates broadcast their programs over the air to customers' antennas or from cable TV providers that now offer streaming. Subscribers without cable TV service receive programs over the air via an a