We currently have around 30 clients using the system all sharing 4Mbit connection and limited to 128k/256k or less
I have recently set up an asterisk box to be able to give voip service to our clients.
This is an old post and someone has already pointed out that 30 clients on 1 radio is too much...but I thought I would add a note here for people doing research. With Cisco's high-dollar APs they recommend (and you can find this at Cisco.com by searching google):
The number of 802.11b phones you can deploy per Layer-2 subnet or VLAN depends on the following factors:
•No more than seven G.711 or eight G.729 active calls per AP
Also, Network World did some actual testing on some super-high dollar APs optimized for VoIP traffic, and running through a special switch that cost many thousands of dollars. They topped out at 11 or 12 concurrent VoIP calls on 802.11b, and reported problems if they went one over that number. Sorry I can't remember more details, but after reading the article, and Cisco's recommendation, I figure 8 - 12 concurrent calls is about the limit for 802.11b...on good quality equipment.
Just my two cents.