All, As usual I have a bit of a strange one. Our customer, Marks and Spencer, are using our WS5100s and AP300s in their stores. Thy have been deployed and operational for quite a while now without too many problems. In the last couple of months they have been looking at deploying a video sending solution into their stores and they have hit a strange problem. They have been testing with a Gefen a WHDI AMN12100 Receiver and a WHDI AMN11100 Transmitter which as far as we are aware operates in the 5.7GHz band. They are finding that an AP300 set on channel 40 (5.2GHz) is effectively destroying the signal, but set it on any other channel in the 802.11a band and there are no issues. They have even changed the country code on the WS5100 to US and used a channel that should sit right over the top of the 5.7GHz channel the video send it using and they see no problems. Now that all implies that the video sender is not operating in the channel it says it is, however, they have tried other equipment on Channel 40 and they don't see any interference. I have some concerns that the equipment they are looking to use is not legal in the UK as it is sitting in a frequency that requires a license, but despite that can anyone think why we (and only us) using channel 40 could be interfering in this way with a channel 500MHz away?? The Switches are running 3.0.2.0-008R firmware if it makes any difference. Cheers, IJ