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OWA Light vs. Exchange ActiveSync on Windows Mobile devices

Are you wondering whether to use Outlook Web Access (OWA) Light or Exchange ActiveSync for email messages on your Windows Mobile devices? This tip details how each method affects mobile device battery life, security, ease of use and cost.

When using Microsoft Windows Mobile devices, is it better to use Exchange ActiveSync or Outlook Web Access (OWA) Light to access your email? Although one method isn't necessarily better than the other, the best choice depends on how you use your mobile device. In this tip, Microsoft MVP Brien Posey outlines how battery life, email message downloads, security, ease of use and cost vary between Exchange ActiveSync and OWA Light.

Mobile device battery life

OWA Light is usually a better alternative for long battery life. Exchange ActiveSync attempts to keep the device up-to-date by downloading new messages as they arrive. This can consume a lot of battery power if a user receives a lot of email. However, if you use OWA Light to check your email, you only consume power while you're online.

Downloading email messages

If you want constant access to information, Exchange ActiveSync is the best choice. When Exchange ActiveSync downloads email, the mail is stored locally on the device. This means that, even if you lose Internet connectivity, you still have access to the messages that were downloaded. For example, if you put your Windows Mobile device into flight mode while on an airplane, it won't transmit a signal. However, you can still read email while on the plane because it's stored locally.

Windows Mobile device security

Security on your Windows Mobile device is tricky because you can look at it from a couple of different angles. On one hand, OWA Light is more secure than Exchange ActiveSync because you don't store any data on the device. All data is displayed through a Web interface. Exchange ActiveSync downloads messages, contacts and calendar entries to the device.

On the other hand, Exchange ActiveSync also allows you to apply security policy settings to mobile devices and to perform a remote wipe if a device is lost or stolen. However, if a user is running an out-of-the-box configuration on a mobile device and using OWA Light to check email, then there is no direct control over the device's security.

Ease of use

When it comes to ease of use, I tend to believe that Exchange ActiveSync is a better choice. Windows Mobile has a built-in application for accessing messages, contacts and the calendar.

You can open Internet Explorer (IE) and use it to access OWA Light, although the experience varies depending on your mobile device's screen resolution. While researching this article, I used the Windows Mobile 6.1 emulator to open OWA Light. This method works well, but can be confusing on devices with lower-resolution screens because the various display elements are scattered all over the place. Most users aren't accustomed to seeing OWA Light the way the browser displays it..


Typically, Exchange ActiveSync consumes more air time, so cost is a consideration if you don't have a cell phone plan with an unlimited data plan. Because OWA Light only uses air time when checking messages, it may be a better option for users without unlimited data plans.

About the author: Brien M. Posey, MCSE, is a five-time recipient of Microsoft's Most Valuable Professional award for his work with Exchange Server, Windows Server, Internet Information Services (IIS), and File Systems and Storage. Brien has served as CIO for a nationwide chain of hospitals and was once responsible for the Department of Information Management at Fort Knox. As a freelance technical writer, Brien has written for Microsoft, TechTarget, CNET, ZDNet, MSD2D, Relevant Technologies and other technology companies. You can visit Brien's personal website at www.brienposey.com.

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