Even for isochronous communications such as video, TDM is slow.
But where TDM is optimized for voice, packet networks are optimized for data, so voice and other isochronous communications must be squeezed in the pauses between data packets.
Key features of the SedNet(TM) 1394 Evaluation Stack include control of the OHCI hardware interface and the ability to execute common IEEE-1394 functions, such as, asynchronous read/write requests, CSR read / write / lock accesses, bandwidth / channel allocation, isochronous communications
In laboratory tests, the board supported communication at distances of up to 500 meters node-to-node on multimode glass optical fiber at speeds of 400Mbps for both asynchronous and isochronous communications
IEEE-1394 supports bi-directional asynchronous and isochronous communications
at speed that exceed that of all other serial buses.
The LSI also supports many modes of data interfaces for isochronous communications
including dedicated MPEG-2 transport stream input and output interface, IEC958 audio stream input and output interface, and an output interface to D/A converter.
By utilizing a highly efficient physical layer encoding scheme, an additional 6Mbit/s of bandwidth is available for isochronous communications
and connection-oriented ISDN capabilities -- more than enough bandwidth to run multiple room quality videoconference calls and MPEG video playback at a single, LAN-attached desktop.
Asynchronous Transfer Mode (ATM) technology provides bandwidth and response time, while isochronous communications
support provides WAN connectivity through ISDN public resources.