Port Forwarding

CommCat can control your radio through a LAN (Local Area Network) connection or from the Internet.

If you are using CommCat Mobile in your home, your iPhone normally connects to your LAN through a Wi-Fi connection. CommCat or QSXer runs on a computer (or a direct-connected radio, if you are using an Internet Interface) that is connected to the same LAN. Your iPhone and computer (or radio) have distinct IP addresses that are connected through a router. The IP address for your computer or radio is used by CommCat Mobile to provide data flow. Since all connections are inside your LAN, port forwarding is not necessary.

If you use your iPhone away from your home LAN connection, you connect to CommCat/QSXer from the Internet. To control your radio from the Internet, you must open a pathway through your router to the computer running CommCat or QSXer. This pathway is opened by using port forwarding. CommCat/QSXer listens on an assigned port for data from your iPhone. A router transfers data from one or more computers on your local area network to and from the Internet. Data are sent to specific ports. For example, http data normally uses port 80 or port 8080. The default port for CommCat and QSXer is port 30001. The router must be told which computer on the local area network is using port 30001.

Here are the rules for IP addresses:

1) Every device on the internet has at least one IP address. The IP address is a number that is used to identify a device.

2) Every IP address is divided up into many ports. When one computer sends data to another computer, it sends it from a port on an IP address to a port on a second IP address.

3) A port can only be used by one program at a time.