In March 1990 the public telephone adds a new, highly versatile function, with the development and introduction to service of an ISDN-compatible "digital public phone." These phones are able to handle data communication when connected to terminals such as personal computers, and also offer operating help and a time-remaining display as well as on-hook dialing, toll-free and collect calling on telephone cards and cashless calling functions. The result is a major advance in the development of the public telephone.