OK, I have had an idea that's simple, although I'm not sure it'll work. Before I take this further, I have to do some more tests and see if this is really as stable as it seems. But please, read on and tell me what you think:
The objective is to make 2 STDM connections, between the 2x15 DSPs on the chassis and 1x6 DSP on the main CPU, in such a way that:
- it's not necessary to open any of the cases when plugging / unplugging (external connection)
- it's not necessary to remove any card or any STDM connector from the cards at any time (permanent solution)
- The connection is solid but easily removable.
Here's my idea: to make a special STDM cable, using 2 strips of 20 connector flat ribbon cable, 4 regular STDM connectors, and a 40 connector IDC male plug (this is like the IDE connector on older hardrives) -
http://www.connectworld.net/cgi-bin/iec/ID40M .
This male plug can
join both strips (20+20 connectors= 40 pins), and be placed
outside the chasis. If the cables are joined in the middle (with the regular STDM plugs on the edges) we would have the added benefit of keeping both 15 DSPs connected to the outer plugs even when the other card is not connected.
Then, we would need another special cable, but even simpler: another 40 pin plug connected to 2 20 contact ribbons, one for each STDM connector, and this plugs into the 3rd board.
So now we have: 2 cards on the chassis, connected via STDM internally, and with an open middle plug outside of the box; and one card inside the DAW, with 2 STDM connectors linked to an open plug outside the box.
To connect the two, we simply have to use a round IDE cable! This will connect all 40 pins, and put the 6 DSP in the middle of the STDM bus. The cable should really be as short as possible, but it's easily available and much nicer than 2 strips of flatcable...
Things to watch out: the number of the pins has to be well noted, so that pin 1 is the same in all cards, and STDM 1 is the same as well. IDE plugs are assymetrical, so there's no risk of accidentally reversing it. Also, the cables will have to be folded 90 degrees inside the chassis - that should be done carefully.
Alternatively, one could use SCSI cables, that have 50 pins (I think).
So, what do you think? It seems to make sense, but I might be overlooking something, and I would really appreciate your input.
I'm also starting to get a flashback, as I can't seem to find stores in europe that sell these sort of parts... It's quite complicated to read through those part catalogues, the link above was the only one I could find, but if I go ordering from the states it's going to get expensive... So if you know of any, and can direct me...
Well, let me know your ideas!
Cheers,
T
EDIT: In fact, I found that IDE cables and plugs cannot be used, because they have a "blank" pin that reduces the number of connections to 39... But there are 40 pin IDC connectors that could be used in the manner I said above, only flatcable will have to be used for the connection instead of the round IDE cable. Not so good looking, but it's supposed to stay on th shelf, anyway...
its just asus floppy cable reduced to 20 (take of 14 they are 34 conductors). I stopped using floppies ages ago but they keep giving me those 
...
