Software suite to interface a ventilation system (Zehnder, storkair) with external entities, multiples clients are handled A server module interfaces with the ventilation unit via an SR232 (serial) connection Clients connect to the server either via TCP/IP connection or via a virtual serial device provided by a socat instance (the later being use by clients such as FHEM, see www.fhem.de, Device comfoair) The intend is to make it also available for hardware devices (Comfosense, CCEASE) connecting via another serial port. A library is provided that takes care of the protocol. The server and clients are written in Python. Example clients are provided, command line client.py outputs a json structure with data read from the ventilation unit, VMCmysql.py reads a set of data and writes them to a mysql database, a set of web pages and associated cgi clients provide web access to the ventilation unit.