A data access system comprises a plurality of intelligent terminals capable of selectively receiving data from a data bank by means of barge-in telephone lines. Each terminal includes a basic terminal into which application modules and device control modules may be plugged. The application modules contain programs enabling the computer to perform specified functions in conjunction with certain stored subroutines within the basic terminal. A device control module enables communication by telephone with the data bank. A terminal subscribes to the data bank by transferring selectively subscription data to memory within the terminal. In one embodiment, subscription data identifying by serial numbers the terminals which are to become subscribers is circulated on subscription barge-in telephone lines. If a terminal calls a subscription line on which there appears the serial number for that terminal, the subscription data for that terminal is permanently stored within the application module of the terminal. The text data to which the terminal has subscribed is retrieved from the data bank by calling a barge-in telephone line (on which such data is circulated) if the stored subscription data shows that the subscription is in effect.