National Datacast Incorporated (NDI) is a pioneer in data broadcasting. It is a for-profit subsidiary of the Public Broadcasting Service (PBS). it handles datacasting on PBS TV stations throughout the United States. Services using ATSC digital TV include MovieBeam and UpdateTV, for which bandwidth is leased by other companies.
It uses line 21 and other vertical interval lines for data transmission.
- Jones, Graham A.; et al. (2007). National Association of Broadcasters Engineering Handbook, 10th ed. Focal Press. p. 1458. ISBN 978-0-240-80751-5.