As I have mentioned in the past, it is often very convenient for measurement purposes to have a board that breaks out signals of a connector or cable assembly to SMA connectors. This can allow you to connect the transmitters to an oscilloscope at the end of the transmission channel or allow you to make TDR or VNA measurements of your transmission channel. I found some test boards for the Infiniband cable / connector from FCI . The FCI web page is hard to navigate and find new things on unless you know what you are looking for. I actually found these breakout boards mentioned on Wavecrest's web site and then contacted FCI to get the part number. The part number for the 4 lane cable breakout board is 10028105. If you search for this on FCI's web site you will be taken to a page that allows you to either see the datasheet for this part or browse for other infiniband test accessories (referred to as EyeMax Accessories).