There is no limitation on the number of IP phone connected to the
24 10/100 port available. The only thing you need to check is the aggregation bandwidth
to your distribution layer.
each IP phone use G711 i.e 64 KB/s bandwidht per voice call at the least in
pactice you'll consume abour 86kb/s second per voice call. So if all
24 port are actively in a voice conversation, then you need an aggregate uplink that
can support 2.064 Gig.
Since the WS-C3524-PWR-XL-EN as two gig uplink interface,
you can have effectively 23 phone but you'll have to port
channel the gig interface to aggregate the bandwidht to 2Gig.
