An open lined phone can be used with any GSM network.
An open lined T-Mobile Dash can connect and make calls on any Global System for Mobile Communications (GSM) network. To accomplish this, you must unlock the SIM card application from the T-Mobile network using a special unlock code that is unique to your handset. In many cases, T-Mobile will provide the unlock code for T-Mobile Dash free of charge.
Instructions
1. Turn on your T-Mobile Dash. Dial "*#06#" and press the green call button. Write down the IMEI number that will appear.
2. Call T-Mobile customer service to request the unlock code for your T-Mobile Dash. Give them the IMEI number and an email address to send the unlock code to you.
3. Follow the unlock code instructions when you receive the email in one to two days. Enter the unlock code carefully to avoid errors.
4. Remove the battery panel and the battery from the T-Mobile Dash after you have finished unlocking the phone. Remove the T-Mobile SIM card from its holder and replace it with a SIM card from another mobile network. Replace the battery and the battery panel. Use your T-Mobile Dash as usual.
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