To all O2 UK customers:

Have you:
- Ever noticed calls go straight to voicemail?
- Ever sent a text and noticed that old ones came in at the same time?
- Ever knowingly not received a text straight away, even though you can see you've got signal?
- Ever been given the 'silent treatment' when trying to establish an outbound call?

O2 UK have long suffered with a fault whereby subscribers 'drop off' the network, despite the handsets concerned being switched on and in coverage. During this period of time, the phone is essentially offline until something happens to make it re-register. This could be someone trying to call you and getting voicemail first time around, you trying to make a call, or you sending a text.

Here's a little example of what the rest of the world sees when an O2 subscriber is stuck in this 'state':

MSISDN: 447590xxxxxx
Status: Unavailable
Network Code: No Network Code
ErrorCode: 1b
ErrorDescription: MAP_ERR_ABSENT_SUBSCRIBER
Prefix: 447590
Organisation: Telefonica O2 UK Limited
Network: O2
Country: UK

This is the response from O2 UK's Home Location Register, which basically keeps track of all of the subscribers. It's saying that in this case the subscriber, which happened to be me, is offline.

Here's how it should look:

MSISDN: 447590xxxxxx
Status: Success
Network Code: 23410
MSC & Location: 447802xxxxxx GBR
Organisation: Telefonica O2 UK Limited
Network: O2
Country: UK
Ported: No
Prefix: 447590
Organisation: Telefonica O2 UK Limited
Network: O2
Country: UK

Without access to a HLR Lookup facility it can be difficult to know that your phone is in this state - given that any action on your part will probably cause re-registration and if you've got texts waiting to come to you, well, you wont know until it's too late.

However, for now, please post your own experiences of this issue. I have contact details for the network engineers department at O2 and if we can put together enough information I'll pass the details on.