Lines are the objects of D2000 system, which defines the transfer parameters via physical line. They are defined by logical names and relation to communication process. In the system, there may be defined several communication lines (real limitation is not implemented, limits in the system may result from maximum number of threads in the system and the capacity of available memory). For each defined line in D2000 system, own communication subprocess (thread) is created, that performs independently the communication for all Stations belonging to this line. Communication via several lines is performed in parallel, communication process is, with regard to communication lines, re-entrant.
Object hierarchy - Communication process, Line, Station, I/O Tag
EXT_KOM external communication process is in D2000 V4.0 is substituted by the interface for external communication protocols, that is implemented as DLL libraries.