Important Cloning Details
The null-mdm cable MUST have the full complement of signalling wires.
That means it is best that there are 8 wires in the cable jacket.
Simple null modem cables with shunted RTS DTS or DSR DTR are not good enough.
The coolsat developers were tricky in their use of the serial ports, using some of the serial hardware control wires to signal whether or not the receiving STB was properly ready for getting a firmware download.
Some simple null-mdm arrangements have the sending STB decide the other end is not ready, and in the menu system, instead of being off.
Another null modem arrangement I tried - with a serial diagnostic "patchbox" had switches that allowed two straight through cables to become a null-modem via the patchbox. Something about the patchbox did not emulate the cable assembly closely enough, and I had to resort to a complete, and simple wire-only cable.
This following diagram should help. If the X's don't line up, then try viewing the diagrams with a mono-spaced font.
DTE (9 pin) DTE (9 pin)
RD 2 ---------\ /------------- 2
TD 3 <--------/ \------------> 3
RTS 7 ---------\ /------------- 7
CTS 8 <--------/ \------------> 8
DSR 6 <---, ,----> 6
DCD 1 <---+----\ /-------+----> 1
DTR 4 ---------/ \------------- 4
SG 5 ------------------------- 5
Note:
2,3 are switched over, as are 7,8 and 1,4
Both connectors should have 6 shunted to 1
Only 5 is straight through. (Signal Ground)
Ideally developers should avoid using hardware features for purposes other than intended, and because of this, CS developers made the use of a serial cable break-out box (An important diagnostic tool) problematic.
If any future developers are reading this, then try to avoid this sort of tricky design jiggery. It compromises the implementation standards, in this case making the serial port fail to conform to IEEE rs232 standards. Good design engineers don't flaunt standards this way.
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SatWiz - Lumbago class
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