This function has no return value.

This function causes the device to make a call to the telephone number designated by the phoneNumber argument. Not all devices support _x_phoneTo(). You can determine device support by calling the _isSupported() function with the entity value &_X_PHONE_TO;. See Device Independence, Determining Device Context, _isSupported() function, Feature Support Information Entities. 

Note: Devices which otherwise support _x_phoneTo() may not support it for specific applications, based on security options.

Depending on the device, the UJML application may be suspended while the telephone call is in progress or the UJML application may be unloaded before the telephone call is initiated.

Scripting, Using Functions, Device Independence, Determining Device Context, _isSupported(), Feature Support Information Entities.