Yes, it will allow 3550, 3560, 3750 in IOS 12.2(36)SE and above. The Cisco Catalyst 3750 Series is available with either the IP Base image or the IP Services image. 3750G-48PS Switch can provide 7.7W inline power to all 48 ports so if your ip phones which needs less than 7.7W will work on all 48 ports.