How to prevent child from calling friends?

Question

Even when the phone is locked to the maximum extent (bedtime on Google Family Link / Huawei parental controls), the child able to call friends. This is not what I want, especially during nights.

I have spent a lot of time looking for a solution. This seems like something easy to implement (even locking the whole dialer app), however it looks like one would have to root the device to achieve this.

I found one trail, MMGuardian, that claims to allow contacts white list, but this is paid software and I'm looking for a free solution.

There is a Google topic about this, on which a lot of people voted.

How come such a seemingly obvious functionality is not available?

Answer 1

I haven't been able to test this (due to a lack of that setting on my daughter's card), but it seems one can achieve it by setting FDN (fixed dialing number) - a SIM setting, though changing it doesn't seem very easy comparing to other parental controls.

Fixed Dialing Number (FDN) is a service mode of a GSM mobile phone's SIM card. Numbers are added to the FDN list, and when activated, FDN restricts outgoing calls to only those numbers listed, or to numbers with certain prefixes. A notable exception is that emergency calls to 000, 112, 911, 999 and the like are exempt. Incoming calls are not blocked by FDN.

One practical application of FDN is for parents to restrict the phone numbers their children can dial. The SIM card's PIN2 must be entered beforehand or when applying such settings.