the 8110 and 3410 are not DCT4 phones. You can only actually remotely unlock DCT4 handsets (3510i, 8310, 6100, 6610, 7650, 3650 etc - any phone with GPRS basically). You can download a DCT4 calculator from the Internet which allows you to unlock a DCT4 handset by entering the IMEI of the handset, selecting the model from a list and selecting what network it is currently locked to - it gives you 7 codes to enter, the 7th is the universal code (unlocks all locks), but if that doesnt work, the 1st and 5th are the ones to use (note: you only get 5 attempts to unlock a locked DCT4 phone by code - after this, its a cable job only).