Asterisk
An open source communications platform, asterisk® is a complete ip pbx in software. it runs on a wide variety of operating systems including linux, mac os x, openbsd, freebsd and sun solaris and provides all of the features you would expect from a pbx.
http://www.asterisk.org/
Alcatel
Alcatel
http://www.alcatel.com/
3com
3com
http://www.3com.com/prod/nl_be_emea/prodlist.jsp?tab=cat&cat=23
Ericsson
Ericsson is shaping the future of mobile and broadband internet communications through its continuous technology leadership, helping to create the most powerful communication companies in the world.
http://www.ericsson.com/
Exa-omicron
Exa-omicron
http://www.exa-omicron.nl/astium-voip-telefoon-centrale
Panasonic
Panasonic nederland
http://www.panasonic.nl/
Nec
Nec global gateway
http://www.nec.com/
Siemens
Siemens
http://www.hipath.nl/