Configuring Ciscos CallManager 4.0 and above to use NTP is not as simple as it should be. First at all, CCM 4.0 is using Windows 2000 as a base system and NTP nor SNTP is enabled there per default. Especially Win2000 is using SNTP, therefore CCM 4.0 is installing a separate NTP service which has to be configured separately.
The NTP configuration file can be found under C:\WINNT\system32\drivers\etc\ntp.conf choose your favourite text editor and add your NTP server.
Minutes later our phones and CCM machine should have a synced time and date.