A line of products created by Voice Technologies Group (since absorbed with Dialogic into Intel).
The Voicebridge products are used to connect to proprietary phone lines on PBXs, and supports Mitel, Lucent/Avaya, Siemens Rolm, and Nortel Meridian.
The product is an ISA card with an SCbus connector, and an HD-50 connector on the outside. The HD-50 connects using a funky cable to a standard Telco plug, such as on a 66-block. They are available in different flavors, one for each of the PBXs supported.
The target market is companies who develop products such as voicemail systems, automated banking, automated attendants, etc.
The cards provide a number of 'virtual' phones on the PBX, acting like a high-end digital set, and providing all of the features of the physical phoneset through the API. The display, line keys, etc., are all available to the programmer.
When Voice Technologies Group was purchased by Intel/Dialogic, no further development was done on the Voicebridge line. All products have been replaced by Intel products which use their own API, which is no longer free for developers.