It can be a pain when buttons on your phone get pressed when in your pocket or bag. You can lock your Sony Ericsson C905's keypad by pressing * then Lock keys (Figure 1 & 2), or you can set it to lock automatically  after a short time.

Enter the main menu by pressing the centre button, then highlight Settings and press Select (Figure 3). Scroll down to highlight Locks and press Select (Figure 4). Scroll down again to highlight Automatic keylock and press Select (Figure 5). Now choose On and press Select (Figure 6).

For added security, you can set your phone to lock with a numerical code. This means that if you should lose your phone, it will require a passcode to be switched on again. You have three options: On, Automatic and Off. ‘On’ means that you will be required to enter the passcode every time the phone is switched on, where as ‘Automatic’ will only require a password if the SIM is changed.

To activate any of these functions, hit the centre button to enter the main menu, then scroll down to the Settings icon and press Select. Now scroll straight down to Locks, press Select, then choose Phone lock and press Select (Figure 7). Before you begin, you’ll need to change the code to something only you know (Figure 8). By default the Phone lock code is set to ‘0000’ so highlight Change code and press Select, then enter ‘0000’ and press OK. Now you’ll need to enter a new code twice in order to activate it (Figure 9).

Once you’ve changed the code scroll up to Protection. Press Select to adjust the protection level (Figure 10). Choose from On, Automatic and Off, then press Select (Figure 11). You’ll be required to enter your passcode to continue, then you’ll see a confirmation message.