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Author Topic: db25 parallel v. serial pinout voltage  (Read 5840 times)

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db25 parallel v. serial pinout voltage
« on: July 17, 2009, 11:55:22 PM »
Hi. I've got a cnc laser from the late 80's and I'm trying to retrofit it to use mach3. What concerns me is the 12 volt pin. If I plug this into my parallel port will this voltage fry my mother board? The pinout is as follows:
MOVER-MPG Reference (1987-1990)
Signal H4 DB25F Pin 
Step1-5 
Step2-6 
Step3-7 
Step4-8 
Dir1-18 
Dir2-19 
Dir3-20 
Dir4-21 
Device0-Enable 9 
Device1-Enable 22 
+12V-11 
+5V-24 
Ground, Logic Common-13,25 
   
Signal H5 DB25M Pin 
Limit1-19 
Limit2-6 
Limit3-18 
Limit4-5 
Limit5-17 
Limit6-4 
Limit7-16 
Limit8-3 
+12V-14 
+5V-13 
Ground, Logic Common-1,12 

Offline Hood

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Re: db25 parallel v. serial pinout voltage
« Reply #1 on: July 18, 2009, 03:05:10 PM »
Yes, if the wire has 12v on it you will kill the port.
Hood
Re: db25 parallel v. serial pinout voltage
« Reply #2 on: July 18, 2009, 06:28:21 PM »
Would a serial port take the voltage?

Offline Hood

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Re: db25 parallel v. serial pinout voltage
« Reply #3 on: July 18, 2009, 06:45:58 PM »
I think RS232 is 12v but  I am far from an expert so take that with a huge pinch of salt.
Hood

Offline Chip

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Re: db25 parallel v. serial pinout voltage
« Reply #4 on: July 18, 2009, 07:24:12 PM »
Hi, Ohpakron

You need to post moer info on your laser setup, Maybe some pic's, how many stepper's, control board's....

Chip

Offline simpson36

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Re: db25 parallel v. serial pinout voltage
« Reply #5 on: July 19, 2009, 06:52:50 AM »
I *think* you can use a 1k resistor in the 12V to knock it down to 5V

BUT, please confirm that with the electron guys before you act on it. I am unqualified in the area of electronics.
Re: db25 parallel v. serial pinout voltage
« Reply #6 on: July 19, 2009, 10:57:02 AM »
Not sure what you are trying to do? if any signal or output pins on the machine end Source 12v then you are going to need an interface of some kind, If it is just the 12v pin you are worried about, why not just leave it open? 
This is if the signals can be operated by 5v TTL.
(RS232 serial is + and - 9v minimum.)
If you do not have a diagram that outlines the nature of the I/O, then you could do a bit of reverse engineering to see what kind of components and signal levels are used to feed the ports.
Nosmo