I've purchased a used BayTech RPC4 unit (8-port power strip controllable using RS232).
The front of the unit has an RJ45 port (EIA-232) and has a wiring diagram on how to wire it to a DB9 port so you can connect it to a PC.
Here's the diagram:
If I use standard TIA-568B wiring for the RJ45 connector:
1 = orange/white
2 = orange
3 = green/white
4 = blue
5 = blue/white
6 = green
7 = brown/white
8 = brown
…then it looks like I need to connect to to a DB9 like this:
1 = DB9 #4
2 = DB9 #5
3 = DB9 #7
4 = DB9 #3
5 = DB9 #2
6 = DB9 #1
7 = DB9 #5
8 = DB9 #6+8
However, that doesn't seem to work. I'm using WinXP HyperTerminal for testing (9600-8-N-1) and I don't get any input or output.
Can anybody help me out? What am I doing wrong?
Best Answer
Update
As I originally predicted, the wiring is proprietary and the flow control signals are a mess. @SofaKng has reversed engineered the official cable and produced this table (reproduced here):
Original
You missed a key detail. Their RJ-45 patch cable is null modem wired. That means it is reversed. You got all of your pairs backwards (you connected TX to TX, RX to RX, etc...)
Assuming you are using a straight-through patch cable...
...it goes this way:
The DB9 on a PC is pinned out this way (see figure). Note how it is null-modem reversed from the table listing you provided. That's because their RJ-45 cable is null-modem reversed to cancel it out. Tricky and silly, but that's how they chose to implement it.
Some other thoughts...
Actually, I noticed from tracing in the diagram that they do some very strange stuff with the flow-control signals. For example, they short CTS and DSR on the PC side, but not on the other side. They route RTS on the PC side to DSR on the device side. And other weirdness.
This may be bad documentation, but I suspect they have implemented custom firmware/software that makes use of the flow-control signals in non-standard ways as a means of ensuring that you only buy and use their cables and adapters.
I would suggest that you make two half cables. On one end go RJ-45 to unterminated wire and the other go DB9F to unterminated wire. Then you can twist your way through all of these weird configurations until you get it right. I would start with my suggested mapping. If that doesn't work, report back and I'll give you my mapping for all of their weirdness in the flow-control lines.
Good luck! =)