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How to powe up a device using serial communication?

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You need to find out EXACTLY what it requires, you've been saying RS232 all through the thread, then suddenly you mention it's connected to a PS2 port, which provides 5V power for a keyboard.

Does it work if you connect it directly to a proper RS232 port?, often these scanners emulate a keyboard, which is why it connects there.
 
You need to find out EXACTLY what it requires, you've been saying RS232 all through the thread, then suddenly you mention it's connected to a PS2 port, which provides 5V power for a keyboard.

Does it work if you connect it directly to a proper RS232 port?, often these scanners emulate a keyboard, which is why it connects there.

And if it emulates a keyboard or mouse the adapter is probably converting info, keyboards and mice are sync type devices.

Do you have the power supply that comes with the device, spec sheet says there is a jack on the connector to use the external supply.
 
actually when i connected the barcode directly through rs232 it didn't power up..

the barcode has no power supply
 
actually when i connected the barcode directly through rs232 it didn't power up..

the barcode has no power supply

According to the instruction posted earlier, you have to configure it for the mode of use you want - it's obviously configured currently as a 'PS2 keyboard wedge'.

However, the instructions show it been powered with 5V by either pin 25 of a DB25 or pin 9 of a DB9 serial port, and none of the serial port pins provide 5V according to RS232 specs.
 
this not a problem with communicating . it's a problem of powering up this barcode without a PC.

Lol, you didn't get it.

I meant, why didn't you say that you were using the PS/2 port all the time?

I believe that you should use a separate power supply. COM ports are not meant to power things up.
 
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Hayato.. Ps2 ports have supply lines for +5 volts. They were designed for it. They're 5 volt serial ports too..
 
Hayato.. Ps2 ports have supply lines for +5 volts. They were designed for it. They're 5 volt serial ports too..

Yes and they are somewhat different from regular serial ports. They are a type of sync comm port.
Check this: **broken link removed**
 
Hyatao, that's simple, posters never provide all the information required to answer their questions.
 
Thanks guys for the useful information

finally , i decided to connect to the micro using ps/2

the ps/2 connector has 1 pin for data(no Tx or Rx)

any idea how can i connect the reader to the pic?
 
It's a syncronous bi-directional protocol, you need to implement that - as already suggested, google for it, there are plenty of PS2 PIC examples on the net.

If in doubt check the PICList.
 
i connected the Vcc and gnd to pin # 4,3 in ps/2 connector

but again the power didn't reach the device

i thought the device will start regardless of data and clock pins values
should i connect the clock and data before it can start ?
 
i connected the Vcc and gnd to pin # 4,3 in ps/2 connector

but again the power didn't reach the device

i thought the device will start regardless of data and clock pins values
should i connect the clock and data before it can start ?

How would we know, it's YOU who has the device.
 
i connected the Vcc and gnd to pin # 4,3 in ps/2 connector

but again the power didn't reach the device

i thought the device will start regardless of data and clock pins values
should i connect the clock and data before it can start ?

Are you sure you are getting the correct pins and not counting backwards?

Does your dc supply have enough current?

I am not sure but I think the device has to supply the clock. You should check the ps/2 specs to verify who does supply the clock.

I think you need a little more reading on your device and maybe get some specifics on it's interfacing, sometimes it's just not simple.

Mike.
 
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