Analog passthrough

Electronics Analog passthrough is a feature found on some digital-to-analog television converter boxes. Boxes without the analog passthrough feature only allow older, analog-only TVs to view digital TV. Those with analog pass-through allow both digital and analog television to be viewed on older TVs. Before digital television, passthrough originally existed in VCRs (and later PVRs and DVDRs) that connected to a TV set using RF connector, allowing the TV antenna or cable TV signal to be switched to pass through the VCR, or have VCR output added as an extra channel. The problem All digital-to-analog converter boxes have both an antenna input (which accepts the coaxial cable that formerly went directly to the TV) and an RF output (which now goes directly to the TV). They may also have additional outputs. Any converter box converts the digital signal for the current digital sub-channel to an analog signal (at the reduced screen resolution of the analog standard), outputs that signal onto analog channel 3 or 4 (set by the user to avoid any conflict with local over-the-air channels) and sends that signal to the analog tuner on the TV. With a box that lacks analog passthrough, no other si