Why can't a full netcom mobile phone put two telecom cards?

When inserting dual telecommunications, the secondary card (non-data card) must be in the VoLTE network, otherwise the secondary card will have no signal.

Opening method of VoLTE

Method of opening or closing VoLTE service by telecom card: To open VoLTE service, send KTVOLTE to 1000 1, or consult the telecom customer service hotline 10000 for manual service.

The method to close the telecom VoLTE service: send QXVOLTE to 1000 1, or consult the telecom customer service hotline 10000 for manual service.

VoLTE service conditions:

1, whether the mobile phone and SIM card support VoLTE；;

2. Is VoLTE network covered locally?

Open method:

Funtouch OS 3.1/IKO Monster UI and above systems:

1. Enter Settings → Mobile Network (Dual Card and Mobile Network) →SIM Card Information and Settings → Select SIM Card → Open "VoLTE HD Call";

2. Enter Settings → Mobile Network (Dual Card and Mobile Network) → VOLTE Call → Open VOLTE Call.

3. Go to Settings → More Settings → About Mobile Phone → SIM card status, and just turn on "VoLTE Call";

Funtouch OS 3. 1 and the following systems: Go to Settings → Telephone and turn on "VoLTE Call".