The Communications Subsystem is the set of Smalltalk classes that support communications over the internet, local area network (LAN) or via a 3270 emulator. VA Smalltalk exploits the Communications Subsystem to provide easy to use parts for application construction.

The Communications Subsystem is divided into three layers:

Each layer exploits the services provided by the next lower-level layer.

The layered design gives you the flexibility to implement applications that use network-protocol-independent application logic. The Communications/Transactions feature supports the following communication protocols by creating a specialization of this subsystem: