As of Q1 2009, N-Trig's DuoSense is the touch input device on three computers: HP's TouchSmart tx2 and Dell's XT and XT2. This makes multitouch available at a very reasonable price, but there is still some confusion on the availability of multitouch. Apparently, this depends not only on the operating system but also on the firmware that is installed in the device.

What multitouch?

The DuoSense is a dual device: it detects both the stylus and the fingers. The finger detection system is able to detect multiple fingers. But at the date of writing and as far as we know:

these two features have not been observed to work at the same time: either you have single touch + stylus, or you have multitouch alone. This results both from observation and from analysis of the HID report descriptors. The HID report descriptors we have either leave room for multiple fingers *or* contain fields for the stylus.

finger tracking is not performed in the firmware. It is done by the software driver on Windows 7.

Of course, if someone has more accurate information, we'll be happy to include it here.

Firmware versions

We have asked a few people to give us the firmware version on their N-Trig DuoSense along with the observed behaviour and, when available, the HID report descriptors obtained on a Linux machine with 'lsusb -v'.

Observed by	On	Win	Firmware	Win driver	Software bundle	Behaviour	Default descriptors	Analysis
Rafi Rubin	xt		3.2.11.3.5	1.23		Pen, no multitouch	not available
Olivier Thauvin	xt2		3.5.5.13.5	1.26	1.88	Pen, some multitouch	link	no multitouch in reports
Stephane Chatty	tx2	7000	3.5.8.8.5	1.26	8.18	pen, no multitouch	link	no multitouch in reports
Pascal Giard	tx2	Vista	3.5.9.8.5	1.26	1.89	Pen, some multitouch	link
Stephane Chatty	tx2	7000	4.2.17.8.5	1.26	8.18	no pen, multitouch	link	multitouch visible in reports
Rafi Rubin	xt	7100	4.3.6.3.5	1.26	2.59	Pen/multitouch		Evidence of mode switching
Stephane Chatty	tx2	7100	4.3.6.8.5	1.26	2.59	Pen/multitouch	link	Evidence of mode switching
Thomas Hansen			4.3.6.13.5	1.26	2.59.0
Stephane Chatty	tx2	7000	4.5.31.8.5		2.184	both pen and multitouch, 3 modes

Contact: chatty at enac.fr
Updated Mar 31, 2010