Sim card not recognized

The LG Optimus Big LG-LU6800 is a CDMA (Code Division Multiple Access) unit. A network (usually a Korean network) connects directly to the unit using its unique code. It doesn`t have a sim card slot. If you want to use it, you need to contact a network provider and register your LG LU6800 for it to get signals in your area, either by prepaid or postpaid service. The device can still be used but without the network call and messaging feature since you will not be getting signals from a network unless you register it. There is a rumorred Mini-sim card slot on a model of the unit. Users use a micro-sim card instead for those unit since there is an issue fitter the prior sim card size. If you are unable to find the sim card slot (visible when you remove the battery) then you most probably have the CDMA version.

If you're not registered with a service provider they will block you as soon as they recognize the sim card. Sometimes it takes a little longer than others. It may be that the vodacom sim came with the tablet and had a trial period. One that 'trial' period expired the block it.

It sounds like your samsung is locked to particular network.. You can remove this network restriction using unlock code.. you can purchase such code from any vendors online like
http://www.simpleunlocking.com/samsung-galaxy-s-duos/rs16wp9/

Do you want to insert other network sim or if your Blackberry Curve 8350I displaying insert sim card,if already sim card inserted.Don't worry i will help you.You can insert other network sim card in the phone by unlocking the phone from current network lock.To unlock Blackberry Curve 8350I use unlock code.Visit the site Wickedunlock.com get unlock code and unlock it easily.Then insert any GSM network sim card.If the phone displays insert sim card even though sim card is already in the phone.Please remove the sim card and replace it correctly.It is because the phone didn't detect the sim correctly.After inserting if it is display invalid sim or sim not valid message on the screen.It is locked to some network,you need to unlock it.To unlock use unlock code.Get code from online site and unlock it.

it is a network problem otherwise it is also sim card problem,your sim unable to caught enough network.

If the Apple's I-Phone is not detect the Sim Card you inserted means it locked to some Network....find in which Country's Network locked now?
then get the remote I-Phone Unlocking service at
Onlinegsmunlock and Unlock it,then You can insert any GSM network Sim card in the Phone it will detect.....Check whether it locked with GSM or CDMA network GSM network means can be Unlocked from Network lock....CDMA network lock means cannot be unlocked....after unlocked it you can use Only GSM Network Sim card...

this is most common when your phone is a branded phone that has been unlocked(branded being it was made to work with a particular network but was unlocked and can now partially work with other networks). in this case, the phone may find it difficult to recognize your sim card, the way the phone is made is in such a way that when a sim card of the network it is branded to is inserted, it would register it straight away but in a situation where it does not recognize the sim card, it is unable to register it. this brings about the sim registration failed.
sometimes you may lose service on your phone too depending on the level on your sim card.
if it happens that the mobile phone was not branded to any network before, then you have to change your sim card to a more developed one(maybe you get a replacement from your network provider because they produce sim cards differently.like the previous ones may not have some features or have a high level of attention and therefore needs to be changed with a more recent one)
hope this helped you? please rate

the phone would need to be a tri or quad band phone the network may not be supported on those clone phones.

Dear, either check for prevent new sim security is active or new sim not active yet.

clean the sim slot with spirit and insert the sim check if it is registerd with the network. advice by dogy