Since fiber optic data transmissions in networking use square waves, it is a digital signal. However, you can also transmit a analog signal over fiber optic, such as a video. It is not the medium that determines the type of signal, but the devices on each end. Fiber is preferred. Let's start with how signals are transmitted in telecommunications. Most systems use a "transceiver" which includes both transmission and. It serves as the bridge between electronic systems and optical fiber, translating digital data into light and back again.