> yes, the 6503/7603 is the same as the 6506/6509/7606/7609; > that is, there are two 'channels' to each 'crossbar'. ... but my Cisco rep tells me that 67 and 68 series modules are not supported in a 65/7603 chassis. Do you have a 65/7603 system working with the new (20Gb per channel) modules installed ? Best regards, Boyan Krosnov