During installation and maintenance, the phones download various firmware files . In order to do this, a phone requests files for an HTTPS server first. If it gets no response, it then tries to obtain the files from an HTTP server. The address of the server to use is provided as part of the DHCP response that the phone received from the DHCP server. If the IP Office system is being used as the DHCP server, the file server address is set as part of the IP Office configuration. For phones installed using static addressing, the file server address is one of the addresses entered during installation.