Hi Jerome,

We bought a 500 Express for our lab a while back to test with and evaluate. It could be used in a small office environment for VoIP but if it were me I would spend the extra $$ for an upgraded model. Didn't love the Gui-only interface and the ports locked up fairly often. Here are 4 other threads that talk about the pros/cons of the Cisco Express 500 (good and bad);

http://forum.cisco.com/eforum/servlet/NetProf?page=netprof&forum=Network%20Infrastructure&topic=LAN%2C%20Switching%20and%20Routing&CommCmd=MB%3Fcmd%3Dpass_through%26location%3Doutline%40%5E1%40%40.1ddda212/0#selected_message

http://forum.cisco.com/eforum/servlet/NetProf?page=netprof&forum=Network%20Infrastructure&topic=LAN%2C%20Switching%20and%20Routing&CommCmd=MB%3Fcmd%3Dpass_through%26location%3Doutline%40%5E1%40%40.1ddd174a/0#selected_message

http://forum.cisco.com/eforum/servlet/NetProf?page=netprof&forum=Expert%20Archive&topic=Network%20Infrastructure&CommCmd=MB%3Fcmd%3Dpass_through%26location%3Doutline%40%5E1%40%40.1ddc4a5b/67#selected_message

http://forum.cisco.com/eforum/servlet/NetProf?page=netprof&forum=Service%20Providers&topic=Voice%20over%20IP&CommCmd=MB%3Fcmd%3Dpass_through%26location%3Doutline%40%5E1%40%40.1dda9dbc/0#selected_message

Hope this helps! And good luck!

Rob