How can I connect my Tobii device with my mobile phones data connection

Most modern mobile phones can serve as a wireless mobile access point. Check your phones manual and settings for "mobile network sharing", "portable Wi-Fi/WLAN hotspot" or similar. Once you enabled the data sharing, you can simply connect your Tobii device as you do with any WLAN network. It is still possible to send/receive text messages via Tobii Communicator (I-Series: connected via Bluetooth, C-Series: using the build in GSM module).
Connecting your Tobii device wireless to a mobile phone:

If you have an internet-capable mobile phone, you can connect your Tobii device to surf the internet or send emails by using the phones data connection. This can either be done via a wireless network connection or by connecting the phone via USB.

Please note: Wireless network (Wi-Fi/WLAN) needs to be activated in the I-Series Control Center or the C-Series Hardware Options. Depending on your countries health insurance system, a separate WLAN license key might be required to use the wireless network adapter. In some countries such as Argentina, Brazil, China and Japan the devices are not delivered with a radio module and cannot use Wifi. Using your phone as a hotspot can be data-intensive and will dramatically reduce battery life. It is also recommended that you keep the device plugged in while the hotspot feature is turned on. Make sure to have a data plan with your mobile phone carrier as this could mean high extra costs depending on your mobile phone subscription.

Connecting your Tobii device via USB cable to a mobile phone:

An alternative option is the so called USB tethering which is also supported by most modern phones. Refer to your phones user manual for "USB tethering" or "use as a wireless modem". The advantage here is that most mobile phones will be powered through USB from your I-Series and don't drain the phones battery.

Please note: Make sure to have a data plan with your mobile phone carrier as this could mean high extra costs depending on your mobile phone subscription.