I purchased a sim card from tmobile to replace my att simcard on my samsung SGH-A707.The new sim card won't work,it sy's incorrect sim and networt lock.

Computer card Unlocking is very Big process,So that You can use the Unlock code....also in computer card Unlocking you need to use Cable,Software,USB port,Boxes etc,so take big time ,it's risk process,cost High also,So that i would suggest the Unlock code the simple method to Unlock Your Samsung SGH-A707 SYNC phone,You need to Unfreeze means specify the Network ,Country it locked now?
You can get the Unfreeze Code at
Simpleunlocking and Unfreeze the Phone from Lock...


Samsung SGH-A707 SYNC Unlocking InstructionsWarning : Do not enter any wrong unlock codes on your Samsung SGH-A707 SYNC mobile phones. If you enter over a certain amount of wrong unlock codes on your Samsung SGH-A707 SYNC mobile phone, your phone may get hard locked and sometimes become unusable.
1 - Switch ON your Samsung SGH-A707 SYNC with a NOT ACCEPTED SIM Card.
2 - Compose : #7465625*638*CODE# (or *#7465625*638*CODE#).

NOT ACCEPTED: We mean, to use a sim card from a network other than the network your Samsung SGH-A707 SYNC is locked to.
CODE: Its the unique Unlock Code for your Samsung SGH-A707 SYNC.
Each Samsung SGH-A707 SYNC mobile phone has an unique unlock code. You can buy the unique unlock code for your Samsung SGH-A707 SYNC mobile phone using the form above.

Important: Stop if you receive an error message. The device may lock permanently if you enter the incorrect code multiple times.

1. See if your phone is eligible to unlock: Mobile Wireless Device Unlocking.
2. Contact Customer Care to request the Mobile Device Unlock code for your phone.
3. Verify the IMEI by typing *#06#.
4. Insert a Non-T-Mobile SIM & turn the phone on.
5. The phone will automatically prompt you to enter the code into an empty field.
6. Click/Tap in the empty field above the "Unlock & Dismiss" options (this will display a key pad on the screen).
7. Input the unlock code provided by T-Mobile.
8. Click/Tap Unlock.
9. The phone will display Network Unlock Successful.

follow this link and info

• http://forum.xda-developers.com/archive/index.php/t-274193.html

 I purchased my data cable for my A707 on ebay for .99c. It works great. You will have to go to the Samsung website and download the software for the Sync. Or you can purchase the flash drive look a like where you place your memory card in it and then you can put your songs on it. By memory card I do not mean your ATT sim card. Some people do not know the difference that it why I am stating that here. 

Try #7465625*746*Code#

Enter the code you got from AT&T.

See if it helps.

Please ask for any clarifications

Please rate the solution as FixYa if found useful.

Thanks
Rylee

give phone a reset.....or change network settings..

you dont have to buy new sim...go to your nearest service senter. hardware failure.... sim sockets or sim ic... thats the problem...

depends on the phone you are using to transfer from. On my sony, for example, i can go to my contact list options and send contacts via bluetooth to another device.

Which phone are you sending from?

Two things:

Are you in an area where they are upgrading the towers to 3g service? Are you going back and forth from Edge service to 3G service. That could cause the click.

And one more thing you could do is pay 25.00 to get a new sim card. Believe it or not this helps sometimes.

Other than that I do not know of any solution or why it is doing that, it should not do it. If its under warranty have att send you a new one (warranty good for a year from the date you bought it)

CARTEEUSMC

Your phone is asking for a code because it is locked to only work with one phone company. If your new sim is from a different company, you can request the unlock code from your old company, they may or may not give it to you (tmobile usually does, ATT/Cingular usually doesn't). The other option is to use a unlocking service, you can find plenty on ebay. If you didn't change phone companies, your new sim card is most likely bad, have your phone company send you another one.