Sensor Technology Limited
Sensor Technology Ltd. offers piezoelectric materials, acoustic transducers, hydrophones, actuators, instrumentation and systems for applications such as marine navigation, geophysical surveys, underwater explorations, broadband acoustic transmission and laboratory research.
http://sensortech.ca/

VIDIX (VIDeo Interface for *niX)
A portable interface which was designed and introduced as interface to userspace drivers to provide DGA everywhere where it's possible.
http://vidix.sourceforge.net/

Ultrasound Field Simulation
Ultrasim
http://www.ifi.uio.no/~ultrasim/

Transducer Beam Characteristics
Bioacoustics Research lab
http://www.brl.uiuc.edu/Projects/Beam.htm

Technical Committee T13 AT Attachment
Responsible for all interface standards relating to the popular AT Attachment (ATA) storage interface utilized as the disk drive interface on most personal and mobile computers today.
http://www.t13.org/

Schatten Design
Manufacturers of products for the music industry.
http://www.schattendesign.com

IMASONIC
Information on high power transducer arrays for therapeutic ultrasound.
http://www.imasonic.com/Medical/TMOverview.php

Art Interface Device
This page is the home page for the Art Interface Device, an open source hardware project produced in co-operation with Interaccess Electronic Media Arts Centre.
http://www.interaccess.org/aid/schedule.html

Tweak
Experimental user interface, possible successor to Squeak Morphic user interface. Has asynchronous event architecture, mixes interface models: class- + prototype-based, MVC + Morphic. [Open Source]
http://tweakproject.org/

Transducers Direct
Transducers Direct ★ OEM Pressure Transducers, Transducer Reseller
http://www.transducersdirect.com/