G4 protocol is not supported by iRidium.
You can control it via the Inet or Locally.
Any HDL module with the actual firmware supports different connection modes:
- Local (with the broadcast address like 255.255.255.255)
- Remote Server (when iRIdium connects to the HDL thrue the remote HDL server or directly via the internet)
Q:
A few days ago I installed the curtains controller from HDL, I had no problem with the installation or with the basic configuration, them go up, down and stop perfectly.
The questions are:
1) How can I setup a button to turn the shutter? The shutter rotate when the motor works in the direction opposite to the last movement for 2 seconds.
2) I can make a curtain opens, for example 40%, with the touch of one button? How do I configure this?
Better yet, I can control the shutter button with a level?
A:
1. Yes, You can use Macros Delay(2000) in Programming Tab or Scritps Command .Set for activate channel and IR.SetTimeout for Delay
2. can not be done 
3. Yes, You can use Level Min = 0, Max = 2 and in Programming Tab send Value of Level in Send Token (Send to Driver Group Macros)
If you use the VPN connection, you cannot work with HDL using the broadcast data.
Set up the conection with "Internet" or "Remote Server" mode, it will help.
Please read Manual, here you can find a properties of Control Panel commands.
Please try: 

IR.AddListener(IR.EVENT_TAG_CHANGE , IR.GetDevice("HDL-BUS Pro Network (UDP)"), function(name,value)
{
   if (name == "Relay 1:Channel 3") {
         IR.Log("Channel 3"+value);      
   }
});