How Does my Android or iOS Device Connect Over Wi-Fi?

How does my Android or iOS device connect over Wi-Fi?

A feature of AppInventor allows users to connect a device to a PC over Wi-Fi to test their apps. Below we explain in more detail how this process works.

To use the AppInventor connection over Wi-Fi, a user must download the MIT AI2 Companion App via the Google Play Store or Apple App Store, and install it directly to your phone.

The MIT AI2 Companion allows users to make a connection between an Android or iOS device and a PC over the MIT RendezVous Server.

The phone or table must be using Wi-Fi and not the cell network for Internet connectivity.

How MIT RendezVous Server works:

1. Your PC checks in with a 6-character code generated by the MIT AI2 Companion

2. MIT RendezVous Server records the IP address of your PC

3. Your device checks in with a 6-character code

4. MIT RendezVous Server records the IP address of your phone

5. MIT RendezVous Server tells the device and computer with the matching 6-character code the other's IP address

6. Device and computer communicate directly using IP

Ideally our network situation should look like this:

Connecting over the Phone Over Wi-Fi Troubleshooting

Try the following steps to troubleshoot your wireless connection:

1. Try to reach from your PC

2. Try to reach from your device

3. If the steps above both work, try using the "ping" command to ping to the IP Address of the phone (displayed by the MIT AI2 Companion in its startup window). If you are using windows, type "ping" + *IP address of the phone* in cmd.exe window, if you are using mac or linux, type type "ping" + *IP address of the phone* in terminal window. Detailed instruction see

4. If all of these steps succeed and Wireless App Inventor still doesn't work, then there may be a firewall between the computer and phone that is blocking ports 8001 and 9987. If you have a "telnet" program you can attempt to telnet from the computer to the phone on these ports. If the connection won't complete, then there is likely a firewall in place that is blocking connections to the phone

If you do not pass step 4, your network most likely looks like this.

Many networks have firewalls set up that block connections to the phone. A way to get around this is to use your own or a local computer as a Wi-Fi router and have all computers and devices using App Inventor connect to the network using the new router. For detailed instruction setting up a computer as a router, see

Why is my phone still not connecting?

Check that your device is connected to Wi-Fi and not the cell network. On some devices and in some locations, even with Wi-Fi enabled, the phone continues to use the cell network. If this is happening to you, you can disable mobile networking (cell phone carrier based Internet connectivity) from your device's settings menu.