The driver handles hardware connection and receipt of 'touch' data transmitted by the device.

Depending on OS and interface configurations, the driver can be set to post stylus data to the OS via virtual touch/pen/mouse devices (Windows / Linux) or mouse device (macOS).

In addition to posting data into the OS, the data is always made available on the driver's API so that UPDD client applications can also directly receive touch data for further processing.

The driver utilises TCP IP port 4146 to communicate with client applications. This port can be changed if required in the UPDD Bootstrap file.

Client applications may be user written or one of our own client applications, such as Console, Test, Commander (gestures and TUIO server) and Annotate.

When UPDD Commander is in use, it can be configured to post touch data into the OS, such that Commander will instruct the driver not to post data.

It is therefore important for the driver's API to function, it has TCP IP access.

One user reported that when creating a secure adhoc network in macOS (an OS that uses UPDD Commander to handle gestures and touch) the touch function stopped working:

sudo networksetup -createnetworkservice AdHoc lo0
sudo networksetup -setmanual AdHoc 192.168.1.88 255.255.255.255

To overcome the problem this created for the API communication, they had to create an alias to allow the API access:

sudo ifconfig lo0 alias 127.0.0.1