There are three company locations: Dortmund (+49231), Munich (+4989) and England (+44). A SwyxServer with ISDN access is installed in Dortmund; at the other locations, there is a separate gateway with ISDN connection to the public network. Furthermore, the headquarters in Dortmund is connected to a SIP provider. This means that there are four trunk groups (3*ISDN + 1*SIP) each with one trunk.