摘要:
An exchange (12) has a cross-point switch that is arranged to couple data transmission between subscriber terminals (16, 18), each having a dedicated modem (34), and at least one assignable modem (148) located in the exchange (12). The exchange (12) comprises fewer assignable modems than a combined number of dedicated modems within the subscriber terminals (16, 18) and, since the cross-point switch (106) is responsive to the data transmission sent via the modems of the subscriber terminals, the cross-point switch (106) thereby acts to concentrate a ratio of dedicated modems to assignable modems.
摘要:
A passive distribution system for electromagnetic radiation using waveguides (10) and couplers (20) wherein radiation from a source (11) is distributed to a number of destination points (12, 13), including means at destination points for determining the power levels received at the destination points and means for transmitting from the destination points to the source location information representing said received power levels.