Cable adapters and connectors receive electrical signals and output optical signals. A cable adapter can receive various data signals in multiple interface protocols at a first electrical connector and provide an optical signal at a second connector. The conversion of electrical signals to optical signals may be achieved at various locations in the cable adapter. A connector can include an optical transmitter for converting electrical signals into optical signals. Such a connector can be provided on an output end of a cable adapter to provide optical signals corresponding to electrical signals received at an input connector of the cable adapter.