how to test serial port

• Sep 10, 2010

• #1

vinodstanur

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In my pc serial port, pin number 3 is showing (negative) -12v with respect to ground pin 5. But in many circuits like serial port pic programmer, IR signal testing etc I had noticed pin no 3 have +ve 12 volt....IS THERE ANY PROBLEM WITH MY SERIAL PORT?

---------- Post added at 08:13 AM ---------- Previous post was at 08:05 AM ----------

ones I plugged a usb pen drive in serial port , without properly looking to the port....I unplugged it within 2 minutes.

 

• Sep 10, 2010

• #2

S

sicheng163

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just use a serial port test software to check if it works normally,
and you can short pin 2 and 3, then send some datas, you will receive the same data,
and all will be showed in that test software

 

• Sep 10, 2010

• #3

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Sharath411

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Just open hyper terminal in your system and short pin 2 & 3 in the serial port whatever you type by the key board the hyper terminal window will show that.

 

• Sep 10, 2010

• #4

J

Jickson88

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Short pin 2 & 3 using som jumper ,and send some data using hyperterminal or putty etc ,if working u get the data u hav sended!!!!

 

• Sep 13, 2010

• #5

incomplete_jerin

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Just short the 2 & 3 pins of the DB9 connector & the data you type will be displayed on the hyper terminal.

 

• Sep 13, 2010

• #6

zoro1

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With shorting pind 2 and3 you are testing only RX and TX ping.Diffеrent programs are sending data to 3 and2 ,but other pins may have U on it/pozitive or negative depends from software/

 

• Sep 17, 2010

• #7

Kurenai_ryu

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as far as i know... the idle state of the TX pin must be MARK (logic 1??) which should be -12V respect Ground Signal (PIN 5)

of course during communication the state switches to SPACE (logic 0) which is +12V respect ground... but it must be idle most the time...

it's hard to believe that other circuits have diferent behaviour as you stated...

 

• Sep 17, 2010

• #8

zoro1

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with IC Prog and Simple JDM programator you can get from COM power to program the PIC MCU,but some of the new motherboards con provide onli 3-4 V on PIN,so it is imposible to use this programmer ,and need extra power.
May be in idle mode is you say so,but it depends on PC OS and drivers or/and programs installed on the PC.

 

• Sep 18, 2010

• #9

vinodstanur

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how to open hyperterminal? I don't know much about these

---------- Post added at 18:26 ---------- Previous post was at 18:24 ----------

my mother board is gigabyte s series G31M-ES2L

---------- Post added at 18:34 ---------- Previous post was at 18:26 ----------

but I installed pic prog software and opened it and simply loaded a hex file...But no circuit is connected to my serial port. Then i tested pin 3 voltage with respect to pin 5(ground) using multimeter. Then i noticed it is -12v! This is making me much confusion...Actually according to the burning circuit the +5v regulator input is connected to pin 3 . This proves that pin 3 should provide positive volt >7 with respect to ground.
Actually, is my serial port the right one (RS232) ? Is there another type of serial port? The male pins in my pc serial port is little bit thick ones when i compared with my friends pc serial port!!:roll:

 

• Sep 18, 2010

• #10

zoro1

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yes it is the com!
If you want by usb/com -for most programmers do not work,but for simulacion is great!

 

• Sep 20, 2010

• #11

incomplete_jerin

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To open the serial port go to START->ACCESSORIES->COMMUNICATIONS->HYPERTERMINAL.......... Get started.......
Regards,
Jerin.

 

• Sep 20, 2010

• #12

dimas_lilik

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Hi, Vinodstanur
Are you sure. It's RS232, not RS 485..?
Because in my computer likes your computer, in my computer only have RS 485, USB dan hiperterminal.
may be you must check again.

 

• Sep 20, 2010

• #13

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nikhil_jain

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test serial port : hyperterminal

best way is to test thru hyperterminal.. check the following link.. in the video section you can see how to work with hyperterminal

**broken link removed**

check out the circuit connections of RS232 as well

 

• Dec 12, 2010

• #14

K

koinonia

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hi guys,

I want to my pC connect to MCU then the data will be displayed on an electronic board. Question: do you have any idea how to program VB so that it can send data thru its USB port to RS232 of MCU..

Really need help..Thanks

 

• Apr 20, 2012

• #15

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Jickson88

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just hav the driver installed for usb to serial port, then ur usb will be recongnised as a serial port, then same way as u do for ordinary serial port .....