Bell's digital dataphone service (DDS)-a fully digital, point-to-point private line system is running nearly two years behind schedule, according to industry sources. Estimates vary on how long it will take AT&T to complete the monumental task of digitalizing the nation's phone network. Few think it can be done this century. Even if Bell wanted to hasten the conversion, the long-term depreciation schedule on its equipment would prevent it.
For more than a decade, data communications sages have been forecasting the imminent demise of the modem-the MODulator/DEModulator that converts computer signals from digital to analog form for transmission over voice telephone lines and decodes incoming data-streams from analog to digital. But the modem refused to die. It now appears that the devices will continue well into the next century because the phone network will become a patchwork of analog and digital lines, requiring modems at each point where a change-over occurs.
