UIQ 3.0 represents a significant evolution of the UIQ interface. Originally designed for touchscreen smartphones, UIQ 3.0 can now operate on both touchscreen and keyboard only devices. To accommodate these two very different styles of device, the UI interaction paradigm has changed. Gone is the mechanism that automatically closed detail records when switching away from an application. It is replaced by a model of application chaining, based on usage scenarios.

The M600i uses what is principally the non-touchscreen UIQ 3.0 UI style, with a touchscreen; creating a hybrid before any of the pure interface implementation have made an appearance. This combination has the advantage of making the M600i usable single or two handed.

The changes in UIQ's interface are obvious from first sight of the main menu.

The status bar, which used to be at the bottom of the screen, is now at the top. It has two significant additions. The first is the status bar menu. This provides quick access to creating new calls, messages, PIM records, and voice recording; accessing personal area networking options; volume settings; time details; and the key lock.

The second addition to the status bar is the task manager shortcut. This provides access to a list of links including the main menu, activity menu and recent applications (which includes recently used but closed applications). A second tab provides a list of open applications, in descending order of last use.

On the Sony Ericsson M600i there is no dedicated button for accessing the task manager, however the phone's shortcut button can be configured to activate the task manager. This is a useful reassignment for those using the M600i with one hand regularly.

With the status bar moving to the head of the UIQ screen its place, at the bottom of the screen, has been taken with three screenkeys. The centre key is the action key to which the principal screen action is assigned, such as viewing a contact, note or picture. The right screenkey is used mainly for the "More" menu, although it can have other assignments in dialogs. The left screenkey is assigned a range of secondary actions, although it can have no assignment at all.

In addition to these screenkeys, there is also a hardware "back" button. Most screens include an on screen back button or "x" icon for closing dialogs. However, a small number of screens include neither, instead they have "Done" assigned to the left screenkey.

Between the status and button bars is the main application area. This is headed with title and view context bar, which displays the application icon, application, or folder name. Where applicable the title bar also includes the back button and view tabs.

Anyone familiar with earlier versions of UIQ will notice that folders are no longer accessed directly on list screens. Rather than having a folder drop down as an integral part of the menu bar, folders are now accessed from the "More" menu. While this is a obvious change to enable folders to be accessed on a non-touchscreen phone, it makes their use less convenient.

As mentioned in the introduction, UIQ 3.0 no longer automatically closes detail records whenever an application is switched away from. This new behavior exploits UIQ 3.0's ability to chain applications.

According to the UIQ 3.0 style guide there are four basic interactions:

• Linking within an application, where back returns to the previous view.
• User switching via the main menu or task manager.
• Linking through a notification icon.
• Linking through a direct navigation link.

Quite obviously when using "back" any detailed record is closed, but this also happens when a direct navigation link is followed. Using the main menu or task manager to switch applications or activating a notification icon however, leaves any detailed record open.

However, on the M600i there seems to be some variation on these rules. To illustrate this take three scenarios based round contacts: sending an SMS, initiating but canceling a call and making a connected call. In each case the communication is initiated from the contact detail record.

When sending an SMS, once the SMS has been sent UIQ returns to the contact record.

In the case of the cancelled call, UIQ also returns to the contact record.

However, if the call was connected then, on hanging up, UIQ returns to the activity menu.

In addition, if contacts is opened from the activity menu (which will be covered in detail in our next look at the M600i) any detail record opened previously is closed. This does not happen when opening the calendar or messaging application from the activity menu.

There does appear to be an element of inconsistency in the handling of linking and switching on the M600i. This, and the sophistication of the UIQ interface, may point to an issue with the M600i. It is a very usable device. However, learning how it works may be a challenge to some users, as interface the behavior appears not be entirely consistent. Having said that, this may be a case of over intellectualizing the interaction behavior. Sending an SMS is not entirely the same as making a call and in many cases may not constitute the end of activity on a contact. By contrast making a call might more often be a definitive completion of activity on a contact details record. However, returning to the contact details after canceling a call makes sense. Similarly, when opening contacts from the activity menu it seems logical to assume that the user is about to start an activity with a new contact, so being taken directly into the contacts list looks like a good choice.

If the M600i's interaction is thought of in terms of the tasks users will want to undertake with the device, its interactions generally make sense. However, it is also likely to divide opinion very much between those who love the way it works and those who don't.

In may respects UIQ has not lost any of its original desire to be a smartphone UI, not simply a translation of a PC interface into a small device. On the Sony Ericsson M600i UIQ offers the mobile user a rich interface, which is designed to work efficiently in context of the typical mobile activities. The interface is also littered with little trick that simplify the operation of the M600i, once learnt.

Overall the combination of hardware buttons and touch screen offers convenient single handed interaction, with the power of two headed operation when needed. This makes the M600i a good day to day phone with the ability to deliver an extra boost to performing less communications orientated tasks.

The next look at the M600i will be examining the phone and PIM capabilities.

See the first part of our M600i review, which looks at its messaging capabilities, here.

For information on developing for the Sony Ericsson M600 visit www.sonyericsson.com/developer/symbian for development information on Symbian OS and UIQ for Sony Ericsson's phones. Full developer specifications for the M600 can be found at http://developer.sonyericsson.com/site/global/products/phonegallery/m600/p_m600.jsp.