Author Topic: RS232 to USB Adapters  (Read 853 times)

wb7ely

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RS232 to USB Adapters
« on: 2019-11-03, 00:28:14 »
I'm needing at least three RS232 to USB adapters to complete my remote installation. Looks like everyone and their brother sells these things on the internet. I want to avoid problems with compatibility issues. Does anyone have a good product to recommend. FTDI any good? Attaching my remote hookup diagram using elecraft KPA and KAT boxes
Thanks
de Dave WB7ELY
//Dave WB7ELY

dj0qn

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Re: RS232 to USB Adapters
« Reply #1 on: 2019-11-03, 03:48:44 »
Hi Dave,

To answer first the easy question about the type of USB adapter: only buy ones using FTDI chips and never
ones using Prolific or unknown chips.

Now to your plans: there are several things that won't quite work the way you want. I will do my best to summarize:

- USB adapters can only be used between a computer of some sort and a device, but never between devices without an
operating system. These require host mode to work, which in turn requires device drivers on the o/s. So going from e.g.
an RRC COM1 to an amp or ATU will require a "real" serial cable.

- I assume that you wish to use CAT from the TS-480, since you show it going to a PC. In this case, COM2 is used for CAT
between the two locations. In other words, you can not use COM2 for an amp or ATU if you use it for CAT, since it must be
between the TS-480's RS232 port and the radio RRC's COM2.

- One good news: you do not need to use USB adapters between the control RRC and the PC. The RRC has its own built-in
USB to serial converter, so you only need to use one single USB cable (that came with the RRC) between the PC and RRC for
both COM1 and COM2 (CAT).

- Since you only have one serial port that you can use for other devices, such as the ATU, amp, rotor, etc., then look at other
serial servers to provide this integration. There are dedicated devices from Microbit: http://www.remoterig.com/wp/?page_id=636
or generic devices, such as those from Lantronix and other companies, e.g.: https://www.lantronix.com/products/uds2100/

- I believe that the Elecraft devices offer a daisy-chained CAT integration, so that some programs such as the Win4K3Suite https://va2fsq.com/
may offer a method to control the ATU and amp using the single CAT connection, but I am not 100% sure.

- For help getting CAT to work, use my checklist that has been posted here several times, e.g.: http://www.remoterig.com/forum/index.php?topic=6556.msg30428#msg30428

73,
Mitch DJ0QN / K7DX


wb7ely

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Re: RS232 to USB Adapters
« Reply #2 on: 2019-11-03, 05:44:00 »
Thanks for your feedback! I am not using CAT, I prefer the good looking TS-480 control panel at my remote operating position. (Note my diagram has the 480 control panel connected directly to the control RRC) So I think you have almost helped me figure out what to do here. Let me make sure I understand. The RRC has (2) COM Ports and I have two remote devices I wish to control, The KPA 500 which has RS232 on the rear panel and the KAT 500 ATU which has a TRS jack and comes with a cable with a USB plug on the other end. So the KPA is a no brainer, it's a straight RS232 (w/ null modem if using COM 1) from KPA to RRC. And that works great using the elecraft KPA utility on the PC.
However, next you state a little gem that I did not know:"USB adapters can only be used between a computer of some sort and a device, but never between devices without an operating system. These require host mode to work, which in turn requires device drivers on the o/s. So... going from e.g.an RRC COM1 to an amp or ATU will require a "real" serial cable."

So then I am screwed if I think I can use the other com port to control the KAT 500 ATU using the TRS-USB cable with a "double female" hooking the whole thing together. Buying a RS232 cable -> USB would be a waste of $. It does not even look like I could use the microbit 1216H module because it still wants a "real" RS232 plug. You state that there are some third party "serial servers" out there. Would those accept a USB plug from the KAT-ATU and output a USB plug at the control end?
Thanks de Dave WB7ELY
//Dave WB7ELY

dj0qn

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Re: RS232 to USB Adapters
« Reply #3 on: 2019-11-03, 06:22:17 »
Hi Dave,

Using CAT has absolutely nothing to do with the control panel. One uses the control panel as you plan,
but most people wish to have computerized control and logging by using CAT on top of that, just like in
the station. You are an exception if that is not the case.

There is no easy way to remote USB ports using simple devices and you can not use it in this case. Instead,
I would look at my suggestion of daisy-chaining the three devices and controlling them over CAT instead. I
can take a look at the Elecraft web site to see what the KAT500 has available, but I do believe that it offers
serial control of some sort and there is a utility available on their web site. I am a K3 user, but never used any
of their other accessories.

So basically you will not be able to do what you want to do the way you planned to do it and need to rethink it.

73,
Mitch DJ0QN / K7DX


wb7ely

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Re: RS232 to USB Adapters
« Reply #4 on: 2019-11-04, 02:31:15 »
Thanks Mitch! Yeah I am behind the 8 ball on cat control and logging. I just hit the log button on WSJT and manually upload the logfile when I get around to it. Ahh, one of these days. I was able to get the pinout of the TRS plug and RS232 Cable :
The cable uses a three conductor shielded cable. The connections:
DE9M Pin 2 - Mini Phone ring
DE9M Pin 3 - Mini Phone tip
DE9M Pin 4 - DE9M Pin 8
DE9M Pin 5 - Mini Phone sleeve
DE9M Shell - Mini Phone sleeve
So I will build that cable and plug it into the remaining RRC [radio end] COM Port and Use an FTDI as you recommended on the [control end] into the PC to run the utility.
Thanks for your inputs
de Dave WB7ELY
//Dave WB7ELY