View Full Version : how exactly does ActiveSync work?

16th December 2008, 11:05 PM
I am trying to gauge how much data my boss will use when he takes his iPhone overseas.

Optus charges 2c per KB in 10KB increments with a minimum of 10KB per data session, so the cheapest data session is 20c.

I understand how fetch email works in terms of data, but how about ActiveSync in relation to Push? Does exchange server only contact the phone (making a data session) when it is has a new exchange item for the device or are the phone and server continuously contacting each other to see whats going on, thereby racking up lots of 20c data sessions even if nothing is downloaded/uploaded?

17th December 2008, 07:05 AM
The device keeps an active connection; and registers the IP of the phone with exchange so that as new mail arrives it is pushed out to the IP of the device. Because the RETARDED mail feature in the iPhone doesn't allow header only downloads all mail will be downloaded immediately which if he's on roaming rates and gets a lot of email will cost a bomb. So, how much will it cost? if the network disconnects the phone it will reconnect there's 20c a go there, and then you just need to work out how much mail he receives a day and multiply by the data rate.

I think you'll probably find he's better off with mail set to manual checking it once / twice a day or waiting till he can get wi-fi access to download his mail.