PC synchronization is seamless through Bluetooth or data cable. The EF81 features a slimmer jack that is not compatible with older Siemens data cables.
Synchronization options are offered under the Organizer menu and allow you to synchronize phonebook entries and calendar events with MS Outlook, Lotus Notes and other Siemens phones.
For that purpose you would need the Mobile Phone Manager software, though.
The EF81 is a fully equipped 3G device supporting UMTS /W-CDMA 2100/ and GPRS Class 10. Besides that, the phone has a tri-band GSM support of 900/1800/1900Mhz. Unfortunately, the mobile doesn't support EDGE or the older dial-up WAP via CSD. You can easily turn off the UMTS functionality if there isn't any UMTS coverage and you want to save battery life. The phone also lacks an IrDa port.
The integrated WAP/HTML browser is an average one. Works flawlessly and does a good job in transforming web pages into the screen format. The bad thing about is that it doesn't employ the hi-resolution display to its maximum since the large screen font size make the browser fit in only a small portion of the actual web site. It would have been wiser to use a smaller font in order to fit in more information on the large display. As usual, it features a KB and time counter for both the current connection and for the total connections made. Time is really irrelevant here, though, since the phone doesn't support dial-up WAP which is usually the only one that is charged per minute.
A very nice feature that the phone offers is the firmware updates through WAP at the dedicated site http://global-repair-management.com
The Organizer features a monthly, weekly, and a daily view and uses the phone's memory so there's practically no limitation of its capacity.
As I already mentioned, the birthday dates of the phonebook entries are transferred automatically to the calendar and are set as an annual reminder. The Organizer menu strangely enough accommodates a Dictating machine which allows for 150 minutes of recording.
It records in .amr format and the recordings can be used as a voice call melody. There is also a world clock with a general map of the world.
The Organizer can be set to Remote Synchronization via the SyncML protocol.