Now that I’ve got the T-Mobile MDA in my hands, the next obvious question is whether the Messaging and Security Feature Pack for Windows Mobile (aka AKU2) will be offered by Tmo. AKU2 contains the update for Windows Mobile 5 that changes the behavior of “push email”. The change allows the push-mail functionality that shipped with Windows Mobile 5 to behave more like the BlackBerry.
The original implementation of push-mail in Windows Mobile 5 had the mail system send a specially formatted SMS message to the WM5 device. The SMS message instructed the device to initiate an ActiveSync session with the defined server. The ActiveSync session would then pull the email to the device during the synchronization process.
With the new update, the process has changed so that the system never uses SMS messages to do this. Many users were put off by the need for an SMS package on top of the data package, on top of the cell plan. In the new system, the WM5 device keeps synchronizes itself with the server over the air.
Once the sync is complete the device sends an HTTP request to the server asking for any changes since the last sync – the catch here is that the request has a time out of (I seem to remember) 30 minutes. If the server has an update to any of the synced data during that time, it will return the request to the device indicating new data. A new sync is done and a new HTTP request is sent to the server again waiting 30 minutes. If there are no new data updates and the request times out, the device simply re-issues the request. This sequence goes on unless either the device or server is taken offline, or the configuration is dismantled.
For the new system to work, the device will make enormous use of the data connection. While the device will be connected almost all the time, data transfer only happens during the request and sync periods. If you have an unlimited data plan, that really takes the concern out of the picture cost-wise. Also, this is fairly battery efficient as simply keeping the data pipe open doesn’t use much power, only when transmitting/receiving.
It’ll be interesting to see how well this system works out. T-Mobile just released the MDA a few weeks ago so I’m sure they don’t have the AKU2 update pending too soon, and I currently have my MDA simply polling my email accounts on a 15 minute cycle. There are real needs for push mail like the BlackBerry and Microsoft’s implementation, but it is not a requirement for me at this time. Neat stuff!