Time display issue on Cisco IP phone 7945G

Noticed that some of  phone models are following rotuer’s clock and others are synchronizing with CUCME time-zone setting.

As you know, not all the countries are following summer time rule. So, when you choose time-zone for the phones, it should be carefully set it up especially in diverse IP phone model under single call-agant.

Also, SCCP version has less option to control, when SIP has time-zone setting option on the phone side. NTP setup. 

Found below useful link for the time-zone synchroniztion issue.

http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucme/troubleshooting/guide/ts_time.html