wireless transmitter/receiver of some sort at the rtu ie rs232 to wireless or rs232-rs485 convertor to wireless if range is better

July 9, 2024


I work in the oil and gas area and sometimes we have remote sites that have local remote terminal units rtu/plc units that are powered by 12vdc and or 24vdc with solar or thermal burning units.

When I have to communicate with these rtus I hook up my laptop to the rtu rs232 comm port via my rs232 to usb convertor which works well enough when I’m near the rtu.

But sometimes the field devices I have to work on can be as far as 500+ feet away from the rtu and I can’t keep going back and forth to adjust field devices and verifying with rtu. Ideally I would like to have a wireless transmitter/receiver of some sort at the rtu ie rs232 to wireless or rs232-rs485 convertor to wireless if range is better. Then I would carry my laptop in the field 500 feet away and with a rs232 or rs485 receiver/transmitter to usb for my laptop and do bidirectional comms between my laptop and rtu.

There is no 120 vac power at these sites so either battery powered wireless transmitter/receiver or powered from rs232 rtu power and my laptops usb?

Sometimes the rtu will be out in the open sometimes they will be in metal clad outbuilding. Would I put wireless transmitter/receiver near a window or would I need a repeater unit as well?

How can I make this work?


Sabatino Ciambotti

You will need two of these

In order notes mention this " build as pair see Bhaskar"

to setup these i will recommend getting a USB modem as well

Yes in this config you will need one of each.

we dont have battery powered RS232. this is something you will have to arrange


So the wireless to usb will receive wireless rs232 and bidirectional control onto my windows computer correct.

Do both of these require DC power what is exact power voltage and Amp for each of these require?

Thank you,

USB modem can power over usb.
RS232 will need 12V/100mA

Thanks I’ll probably put 2 a32 12 volt batteries in parallel to give me the 12 vdc and the 100 ma current, if i need more current i’ll put another a23 battery in parallel.

does my windows laptop computer require special drivers or software to use with =

Industrial IoT Wireless to USB Modem

Thanks Again

Hi @bsub In most cases, simply connecting the device will prompt Windows to automatically install the driver.

However, if you connect the Industrial IoT Wireless to USB Modem to your PC and it doesn’t appear as a COM/Serial port (verifiable in Device Manager), you’ll need to install the driver manually.

You can use the following link to download the driver installer:

Let us know if you have any question.

Thank you,
Eduardo M.