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Carl_at_xrite
01-11-2002, 04:39 AM
Strange problem, I did a pcb design that incoporated an RS232
to USB convertor as well as an RS422 tranciever.
For cost reasons (only internal test equipment) the board needed to be done on 2 layers.
The question I have is :With all of these differential pairs on the board (5) how the heck can you calculate the differential Z without a reference plane?
Or my assumption that is each line has to be calculated as an R.F.transmission line.
Any input on this subject would be appreciated.

Thanks in Advance

Carl