In the VoIP Client section, you can configure the client for IP telephony. IGEL Universal Desktop provides the VoIP client Ekiga (http://ekiga.org). The client allows the use of SIP and H.323. In addition to local contacts, LDAP address books can be used too.
You will find a detailed description of the configuration options in the original documentation for the Ekiga client at http://wiki.ekiga.org/index.php/Manual.