Derfler, Frank J. <br/><br/>
Microcomputer data communication systems / 
Frank J. Derfler. 
 - Englewood Cliffs, N.J. :  Prentice-Hall,  1982. 
 - 129 p. :  ill. ;  24 cm. 
<br/><br/> At cover: a guide to the operations of modems, terminals, electronic bulletin boards, and information utilities for users of TRS-80, Apple II, Heath-89, and other systems.  'A Spectrum Book' 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Data transmission systems.<br/>Microcomputers.