From Safelinks Terms and Conditions....
You may be able to activate the Service on a compatible, unlocked handset You provide Yourself (Bring Your Own Phone or BYOP). Some SafeLink features are available only on SafeLink handsets and will not be available with BYOP. If you are activating your Service with BYOP, you must use a compatible phone that does not interfere with our Service and complies with all applicable laws, rules and regulations.
Devices capable only of using data are strictly prohibited and Your use of any such device is grounds for immediate termination of Service without a refund. You are responsible for ensuring that your BYOP wireless phone is compatible with the Service and meets all Federal laws and standards...