Advanced Question: Making up a serial cable from Cat5.

Tesla

Tesla

Tesla

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I need a 15m serial cable. I have purchased a 15m length of Cat5 and also 2 serial (RS232) connectors.

Pin out data is here: http://www.aggsoft.com/rs232-pinout-cable/serial-cable-connections.htm

The problem I am facing is that in an RS232 plug there are 9 pins, obviously only 8 cables in Cat5. So, which cable can I get rid of.

The Cat5 pin out seems to suggest that when using Cat 5 you either have RI or DSR.

The cable is to be used with an LG plasma between tuner and panel.

Thanks,

Chris
 
Pin-out for a cross-over cable:
1,6 => 4
2 => 3
3 => 2
4 => 1,6
5 => 5
7 => 8
8 => 7
 
Depends on what you're going to be using it for exactly. What protocol are you planning on using? I remember cabling for dumb terminals with only 2,3 & 7 joined.

As for your cable, you know you can buy RS232-RJ45 ends so that you only need a standard Ethernet cable to join the two convertors? Standard use in data centres.
 
MikeTimbers said:
As for your cable, you know you can buy RS232-RJ45 ends so that you only need a standard Ethernet cable to join the two convertors? Standard use in data centres.
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I did not know this, I imagine it's some proprietary protocol or just varying voltages on varying pins to control actions on the plasma display (it only can perform simple functions such as volume, power etc.) Everything else is controlled via the external tuner box.
 
Then I think you need to check the manual or their website to find how it needs to be wired. It is highly unlikely that you would need all eight wires.
 
Pin 9 is Ring Indicator so can be ignored. Note that it's not in basmic's crossover cable. (Did this from memory, without looking at the link. Having now looked it's nice to see I still have some memory left. :cool: )

Jonathan
 
Last edited:
Does it need to be wired as X-Over or straight through?

Does 1,6 mean 1 & 6 or 1 OR 6. If so which is preferred, 1 or 6?
 
Tesla said:
Does it need to be wired as X-Over or straight through?

Does 1,6 mean 1 & 6 or 1 OR 6. If so which is preferred, 1 or 6?
Click to expand...
My diagram is meant to indicate that pins 1 and 6 and sida A should connect to pin 4 on side B.
 
Some serial cables need to be crossovers and some need to be straight through. It depends on how the internal connections of the devices are wired! Check your manual - all of this should be detailed there otherwise you have little to no chance of getting this to work as the cable pinouts will be a guess!
 
Just a thought I had guys, as I am extended the serial cable and not replacing it then surely I should just wire it up as straight through?

(Sorry, should have said I was extending, making a M->F cable)
 
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