Serial connection over network or just use long cable

[timeshifter]

One of my clients has some lab equipment that communicates with a PC over a serial connection. Recently they've relocated the lab equipment and the PC stayed where it was. Had been using a 6 foot 9 pin serial cable to a Serial to USB adapter. Worked fine.

The applications involved won't be updated any time soon, so we need a Serial solution.

I suppose we could get a longer serial cable and run it through the walls and ceiling. Ugh.

Or maybe there's an IP solution?

https://www.amazon.com/Serial-Ethernet-Converter-Device-Server/dp/B00FJEHNSO

Looks like you can even just use software on the receiving end. So just need the unit above and some software. Or maybe two devices - one for Serial to Network and another for Network to Serial (and yet another for Serial to USB that we already have).

My head's spinning.

 

[River Valley Computer]

How far is the run?

 

[Markverhyden]

How far is the run?

Need to know this first. And is it DB9 or DB25?

Serial can be a number of things. What exactly is being used? RX, RX, and GND? If so you can just run cat5 and add a RJ452DB9 adapter. See that all the time with certain POS systems.

 

[Sky-Knight]

Yeah length is a concern. You can use DB9 to modular adapters too: https://www.amazon.com/StarTech-com-DB9-RJ45-Modular-Adapter/dp/B00066HL3W

That isn't Ethernet though... it's a direct point to point use of Ethernet cable. Which is easier to pull!

Google says, RS232 has a 50ft length limit. So if you just need a longer cable, the above adapters plus a 50ft patch cable will do the job.

If you need longer... well you use those Ethernet gateways and PRAY... because not all devices tolerate them.

 

[Moltuae]

Assuming the existing serial connection is RS232 (most are), the industry standard method is to convert it to RS485 (and back again, if necessary). RS485 was developed as an 'industrial serial' solution to address RS232's limitations, providing greater resilience and transmission distances.

https://www.electronicdesign.com/te...between-the-rs232-and-rs485-serial-interfaces

http://www.rs232-to-rs485.com/

There are lots of different RS232/RS485 converters available; some cheap and simple such as this, some a little more sophisticated such as this.

 

[timeshifter]

How far is the run?

If you’re walking it it’s less than 20’. The connector is DB9.

 

[Moltuae]

If you’re walking it it’s less than 20’

How long is it if you're driving?

 

[Markverhyden]

If you’re walking it it’s less than 20’. The connector is DB9.

What's the comm speed (bps)? You should be fine for up to 50' even.

 

[timeshifter]

9600

 

[Markverhyden]

9600

You'll be fine with a standard serial cable or get and extender to use what you already have.

https://tldp.org/HOWTO/Remote-Serial-Console-HOWTO/serial-distance.html

 

[Sky-Knight]

Yeah RS232 maxes out at 50ft as I said above, if you only need 20-30ft, just get a long serial cable. Or make the modular connectors I listed above so you can use a standard terminated bit of cat6 for easier pulling.

RS485 is nice, but it's much slower and doesn't always work. I find the device needs to be 485 itself to get away with that conversion.

 

[timeshifter]

Update: installed the StarTech device today and it worked out just fine. Did have to call support because the manual mentioned a program called VCOM (virtual com port) that was on a CD in the box, but it wasn't there and couldn't find on their site. Turns out it's in the driver download. Tech picked up quickly, was very familiar with the product and got it going.

Essentially you configure the device on network, assign it a static IP. On the PC WinPcap is loaded and VCOM. You end up with a virtual com port in Device Manager.

1-Port Serial-to-IP Ethernet Device Server, RS232, DIN Rail and Surface Mountable, Aluminum, TAA - R

Connect to, configure and remotely manage an RS-232 serial device over an IP network

www.startech.com