The numeric keypad features a 5-way navigation D-pad, two soft keys and the traditional BACK and C keys. Writing a message with it is relatively easy since the keys are large enough and nicely spaced. All the keys are somewhat unevenly lit in light blue. The mechanism of the flip operates nicely and there is no problem to open it even while holding the phone in one hand. Opening it reveals the QWERTY keyboard with tiny plastic keys. The keys themselves have again light blue backlighting and although they are rather small they are easily used even with big fingers. Each key has two characters assigned to it - one letter and one special symbol such as a bracket, a hyphen, a slash, a question mark, an exclamation mark, currency symbols. The top row of the keys has the numbers as alternative symbols. All the special symbols and the numeric symbols are typed by holding the ALT key pressed in the same time. The keyboard also has a SPACEBAR, which activates the phone application when pressed longer. There are also two arrow keys and a CAPS LOCK key. The DEL and BACKSPACE functions share one key, as well as the OK and ENTER keys. There is no BACK key, but you can use the back key on the left side of the phone for that purpose. It is easily pressed with your index or middle finger while holding the phone in hand.
The display of the Sony Ericsson P990 is 2.67" TFT touchscreen with a QVGA (240x320 pixels) resolution, supporting 262K colors. That resolution is greater than the one of the previous Sony Ericsson P900 and P910 models which was 208x320 pixels. When the flip is closed though, the resolution of the visible portion of the screen is changed to 240x256 pixels. That however is reflected in the quality of the menu graphics - their edges become more jagged due to the downsampling. When the flip is closed the touchscreen functionality gets turned off and you can operate with the handset as you would with any other regular mobile phone. There was one problem we experienced with the touchscreen and it concerned an obvious lack of calibration. The display touch reception was slightly offset to the right so instead of pressing directly on a virtual OK button for example you had to press slightly to the right in order for the phone to accept the command. Unfortunately, the phone lacked any option for calibration the screen which is seen on PocketPC devices based on Windows Mobile.
After all, even a smartphone is a half "phone" so handling calls is equally important as any other feature. During calls we saw no problems with P990 - the sound during calls was clear and loud enough. The network signal was always full which is just what one might expect in urban areas with nice network coverage. A bit of a unique feature is the so-called Business telephony which practically means that you can use your P990 on a corporate telephone network via a Corporate switch PABX (Private Automatic Branch Exchange), equipped with a mobile extension port.
When the flip is closed dialing a number is simple as with any other mobile phone. When the flip is opened or off though you should make use of the integrated phone application in order to dial a contact using the touchscreen display. The virtual keys are nicely set apart so that you can press the numbers with your thumb without any mistake even if you have large fingers.
As far as the performance of the loudspeaker is concerned, we are far from impressed. The sound lacked any bass frequencies at all and the loudest ring volume of the handset proved more than insufficient in noisy streets.