摘要 |
A hybrid star LAN has an access unit (1) with a port (30) associated with each terminal (2), the port comprising a port input (8) and output (9). A terminal link (3S, 3R) links the terminal to the port. A bypass link (11) is in parallel with the terminal link, and the time delays of the terminal link and the bypass link are matched by appropriate registers (11, 13). A comparator (14) compares the outputs of the terminal and bypass links to detect errors through the terminal link and controls a selector switch (12). On the LAN, channels are constituted by varying numbers of TDM slots, as defined by a template stored in the access unit. Each terminal stores that part of the template which defines channels which it can use. Each terminal can also store a second or background template which can be swapped in for the current or foreground template when a change of allocation is desired. |