The java communication API is a Java library with extensions for developing communications applications.
The Java Communications 3.0 API is a Java extension that facilitates developing platform-independent communications applications for technologies such as Smart Cards, embedded systems, and point-of-sale devices, financial services devices, fax, modems, display terminals, and robotic equipment.
source: http://www.oracle.com/technetwork/java/index-jsp-141752.html