Data services delivered to a television screen, obtained either via a broadcast TV aerial or through telephone lines, are collectively known by what general term?

Introduction / Context:
In the pre-web era, consumers accessed textual and simple graphical information services on television sets. Some systems were broadcast one-way over TV carriers; others were interactive over telephone lines with a set-top unit or adapter. This question asks for the umbrella term that covers both models when the output is presented on a TV screen.

Given Data / Assumptions:

• Data may arrive via a TV aerial (broadcast) or telephone line (dial-up/interactive).
• Display device is a television set.
• We seek the generic category name spanning these delivery modes.

Concept / Approach:
Videotex is the broad category for interactive or broadcast information services designed for display on TV sets. It encompasses Teletext (one-way broadcast pages embedded in TV signals) and Viewdata (interactive, dial-up services such as Prestel). Telesoftware referred to software distributed via broadcast data channels, a niche subset. Therefore, the most general term that fits both reception paths is Videotex.

Step-by-Step Solution:

Verification / Alternative check:
Historical documentation describes Teletext and Viewdata as variants within the broader Videotex family, which targeted mass-market TV displays with simple navigation and limited color/graphics.

Why Other Options Are Wrong:

• Viewdata: interactive telephone-line variant only.
• Teletext: broadcast pages only; not interactive over phone lines.
• Telesoftware: specialized broadcast of software, not the general service class.
• None of the above: incorrect because Videotex is correct.

Common Pitfalls:
Treating Teletext as synonymous with all TV-based data services; forgetting that Viewdata required a modem and could be navigated interactively.

Final Answer:
Videotex.