Abstract: Data transmission for a cable television system includes transmitting data via a plurality of signals including, but not limited to, in-band audio, in-band video, and out-of-band signals. The in-band data signals are transmitted on scrambled or non-scrambled channels. In-band video data transmission further includes selecting certain lines of the vertical blanking interval for in-band video data transmission, omitting certain equalizing pulses during the selected lines and inserting in-band video data during the selected lines. The several data signals, in-band and out-of-band, have compatible transaction formats to facilitate decoding and data storage processes at a subscriber terminal of the cable television system. A data transmission apparatus includes a data inserter for inserting in-band data in non-scrambled channels, an addressable data transmitter for transmitting out-of-band data and a scrambler for inserting data in scrambled channels.