Data terminal with error checking file transfer mode

摘要

A data terminal having an error checking file transfer mode which tests received data to determine whether it is valid data and transmits an acknowledge or nonacknowledge signal dependent upon the results of the valid data test. This valid data test preferably takes the form of some type of logical redundancy check matching received data signal with a received redundancy signal. Valid received data is stored in an internal random access memory or an external mass memory. The data terminal preferably exchanges hand shaking signals prior to the initiation of data transfer. The data terminal preferably generates a nonacknowledge signal when a predetermined time has elapsed since the last received signal, echoes an end of file signal when an end of file signal is received and transmits a reset signal if the communications are garbled. In the preferred embodiment the data terminal includes a simple processing unit operating under the control of a program stored in a plug-in read only memory.