Here you go....
O2CallAlert is a simple easy to use alternative to Voicemail 901 giving you missed call information free of charge. If you're on another call, your mobile's switched off, you're out of coverage or you just don't get to it in time, O2CallAlert will tell you your caller's number and the last time they called so you can call them back.
If you miss a call, callers will hear a message telling them that their number will be sent to you via text message to let you know they called. If callers withhold their number you won't be sent a text and they'll be told to call again later.
If you miss more than one call, O2CallAlert will send you details of up to four callers with the date and time of their last call to your mobile.
How do I switch on Call Alert?
You can switch on O2CallAlert at any time by calling 1710 free from your mobile.
And if you want to switch if off, just call 1760 free.
Note: If you are a current Voicemail 901 user and you dial 1710, you will replace Voicemail 901 with O2CallAlert. You will need to dial 1750 to switch Voicemail 901 back on again or 1760 to switch it off.
How much does it cost?
O2CallAlert users pay nothing to receive the SMS either in the UK or whilst abroad. Callers to an O2CallAlert user will be charged as per their standard tariff rate for a mobile terminated call, unless their number is withheld (when they will not be charged for the call).