For users satisfied with eight colors and not needing high-level graphics, Prestel offers an inexpensive and technically proven alternative between ASCII devices that have virtually no graphics capability and NAPLPS devices, which are much more expensive.
IBM's main videotex product is the Series 1 Videotex System (SVS/1), which supports both Prestel and NAPLPS display protocols (see "Understanding Videotex and Teletext Services" box).
Its main videotex product is the Series 1 Videotex System (SVS/1), which supports both Prestel and NAPLPS display protocols.
PC/Videotex supports NAPLPS graphics and allows videotex frames to be captured and stored in a library on a disk for replay later.
Interestingly, AT&T has dropped its own NAPLPS standard in favor of ASCII for the service.
Known as AT&T IVS-5, the software supports a variety of computer-based information services using either NAPLPS, Prestel or ASCII protocols.
Keyfax supports both NAPLPS and ASCII display protocols, making it accessible to virtually all home computers.