An arrangement is employed where a switching unit that conferences a remote telephone with other telephones pursuant to requests that originate via a digital connection from a site that includes the remote telephone. In one illustrative embodiment, the switching unit is an ISDN telephone coupled to a PBX. The remote telephone is connected to a conference point within the PBX via the PSTN. The requests from the remote site originate from a computer, and the digital connection comprises a packet network. Advantageously, the communication through the packet network is encrypted. Conferencing is initiated and controlled by the computer at the remote site, by communicating with the PBX via the ISDN telephone. In another embodiment the switching unit is adapted to create and maintain a plurality of conference calls, pursuant to control signals arriving at a port of the arrangement that is part of the digital connection.