The EP 0 848 568 A1 and the European Patent Application with the Application No. 99 126 221.3 which is filed by the Applicant of the present invention and herewith incorporated into this specification describe e.g. coaxial interfaces between two IEEE1394 serial bus systems, i.e. sub networks, to build a distributed IEEE1394 network.
Generally, networks according to the IEEE1394 standard work only with nodes with short, direct interconnections, since very strict timing requirements, e.g. during the self identification phase (in the following self ID phase), have to be fulfilled. For example, standard wired IEEE1394 networks are limited to 4,5 meters length for every cable.
To build networks which are e.g. not only set up in one room, but inside the whole home plastic optic fiber (POF) implementations are known to ensure longer transmission paths. However, these POF implementations have the disadvantage of requiring a new plastic optic fiber cabling inside the home.
On the other hand, coaxial cable is available in many homes, since such cables build the basis for current radio and television reception, but the channel encoding/decoding required when setting up a network with coaxial cable according to the IEEE1394 standard produces a significant delay. Therefore, a transparent self-configuration according to which every node within the network knows which other node is connected as used for a POF implementation is not possible. Wireless transmission is even more convenient, but the transmission technology also produces significant delays for which reason a special adaptation is necessary which is not included within the IEEE1394 standard.
An extension to the IEEE1394 standard, namely the DRAFT IEEE1394.1 standard tries to enable connections of IEEE1394 networks through a bridge, but inherits two main disadvantages, namely that (1) this standard is not 100% backwards compatible, and (2) the controllers within the IEEE1394.1 network must be aware that bridge devices exist, i.e. the IEEE1394.1 network is not fully transparent in both communication directions between two sub networks.