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R232 25pin to 25pin cable
Posted: Tue 23 Apr , 2013 21:30 pm
by Large519
Couldn't seem to find links regarding 25 to 25 pin r232 cables only 9 pin to 25 pin cables,
Are the following pin connections correct for a 25pin to 25pin r232 cable
pc to cnc control
txd 2 to 3
rxd 3 to 2
rts 4 to 5
cts 5 to 4
dsr/dcd/dtr 6to8to20 - 6to8to20 in each connector
signal ground 7 to 7
cabinet ground 1
Re: R232 25pin to 25pin cable
Posted: Wed 24 Apr , 2013 10:39 am
by Denford Admin
It all depends on what you are connecting to.
Some machines have cable on the inside of the machine which crossed pins 2-3 and 4-5 so that a (cheaper) pin to pin cable could be used externally from machine to PC.
What you've shown is likely to be correct.
6,8,20 linked
7 > 7
1 > shell/shield
2 > 3
3 > 2
4 > 5
5 > 4
Further confusion can arise when using 9-pin connectors.
The 9 pin standard swapped pins 2,3 so that a 9 to 25 way cable would be 2 > 2 and 3 > 3
Re: R232 25pin to 25pin cable
Posted: Wed 24 Apr , 2013 13:11 pm
by Large519
Thanx for the confirmation,
Is it just the pc end connector that needs to be ground to the shell/shield or both ends?
Re: R232 25pin to 25pin cable
Posted: Wed 24 Apr , 2013 13:45 pm
by Denford Admin
Is it just the pc end connector that needs to be ground to the shell/shield or both ends?
Another area of doubt, some people recommend one end only, others both - try connecting at one end only to start with - if you get noisy/unreliable comms then try both. Keeping the cable length to a minimum will help.
Ground loops can cause problems depending on how and where the PC and machine are wired.
https://en.wikipedia.org/wiki/Ground_loop_(electricity)