| 摘要 |
A communication network which uses an infrared backbone and having a radio frequency backup channel is disclosed. The infrared backbone is generally located on a ceiling in a hallway of a building and comprises a plurality of hub access points. The hub access points communicate data on the backbone in a relay fashion using modulated infrared light. If infrared communications fail, the hub access points may, as a backup, communicate in the same fashion using low power radio frequency (RF) transmissions. Each of the hub access points also communicate with one or more non-backbone tap access points using infrared or RF transmissions. Tap access points are generally located on the ceiling in the hallway near an adjacent room and/or at some location in the adjacent room itself. A tap access point in the hallway is hard-wired through the ceiling to another tap access point or an antenna in the room, which permits communication with an end-point device in the room using infrared or RF transmissions. Again, RF may be used as a backup to infrared. The access points use a sequential polling protocol and relay data throughout the network. Absorptive triangular shaped panels are used to absorb and deflect infrared transmissions.
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