RS232 to RS485(2 wire) converter

[plcnovel]

Hi Guys
Is there a way i can convert RS232 signals into 2-wire RS485 signals without using any Hardware, just for testing purposes. I am planning on getting some converters later on.

Thanks

 

[jvdcande]

Because RS232 uses +12V and -12V signals and RS485 only uses 0V and +5V signals, it'll be next to impossible to do a conversion without any hardware. I have had some RS232 cards in the PC which responded well to 0V and +5V signals, but I've never had any that sent 0V and +5V signals out.

Kind regards,

 

[keithkyll]

Many laptops cheat and only send out 5 volts.
There's some old threads about cheating GE PLC's. This method might work. It's been posted several times, so you shouldn't have trouble finding it with a search.

 

[raviv]

Rs 485 Use +12v/-7v Signal And A Difrent Method To Proces The Signal.
It Is Impusible To Do That With No Hardware Device.

 

[bernie_carlton]

I've seen the RS232 cheat sometimes work for going to RS422 but not for RS485 2-wire where the Transmit and Recieve are combined onto one set of wires. I'd say get a convertor now, they aren't terribly expensive.

 

[keithkyll]

Oops, I missed that. The 'cheat' won't work. Thanks for the correction, Bernie.
RS232 uses levels above and below ground. RS485 doesn't have a ground reference. It references to the other wire. It sends it's ones and zero's by swapping polarity.
I think both RS422 and RS485 use this method, and the difference is 4 wire vs 2 wire.