Source of version: 10 (current)
Exchange ActiveSync is extension of Exchange 2003 that allows a Pocket PC or Smartphone (2003, 2003 Second Edition or Windows Mobile 5.0 or Windows Mobile 6 device)synchronize with directly with an Exchange server (as opposed to the older PC based ActiveSync). Microsoft provides Exchange ActiveSync for free with Exchange 2003. For the special form called ((DirectPush)) the server needs to have Exchange Server 2003 SP2 installed.
The original implementation of Exchange ActiveSync requires the client to poll the server. On the mobile device you can specify the interval for this polling. Shorter intervals will put more strain on the battery of the device.
Unfortunately, with Windows Mobile 5, Microsoft have selected to make the polling the default setting of ActiveSync. As a result you may see your device wake up regularly without any real need. To avoid that you have to apply what is now known as the "((Fake Server Hack))". This is necessary because without a server set up you cannot change the sync schedule to "Manual". (You can remove the fake sever again after you changed the settings).
With Exchange 2003 Service Pack 2 and Windows Mobile 5.0 AKU2, Exchange is now able to push e-mail directly to the Windows Mobile device. This is called ((DirectPush)).
Smartphone 2002, Pocket PC 2002, Windows Mobile 2003, Windows Mobile 2003 Second Edition do not support this form of e-mail push. They may support the previous version that uses SMS messages rather than long-time TCP requests. Dataviz offers [http://www.dataviz.com/products/roadsync/winmobile/index.html|Roadsync] for Windows Mobile 2003 and Windows Mobile 2003 Second Edition Pocket PCs to use push e-mail with Exchange 2003 Service Pack 2.
Prior to Exchange 2003, Microsoft released Mobile Information Server for Exchange 2000. This was the first release of synchronization software for Exchange however it was not free. Microsoft no longer offers Mobile Information Server for Exchange 2000.
[http://www.pocketpcfaq.com/faqs/activesync/exchange_errors.php|Exchange ActiveSync Error Codes]
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