International Direct Dial with international format (plus "+" sign)
i.e. +65123456

Using IDD Access Code 001 or 007
You can dial access code 001 or 007 followed by the country code and phone number
i.e. 007 65123456 or 001 65 123456

Using VOIP Access Code 01000
If you are using XL Axiata mobile number, you can dial using VOIP dial code 01000 followed by the country code and phone number.
i.e. 01000 65 123456

Using VOIP Access Code 01017
If you are using Telkomsel mobile number, you can dial using VOIP dial code 01017 followed by the country code and phone number.
i.e. 01017 65 123456

You can dial access code 001 or 007 followed by the country code and phone number
i.e. 007 65123456 or 001 65 123456