[Elecraft] Any ideas on how to run serial (DB9) and USBserial at the same time?

[David Orman]

Hi,

I picked up a modem splitter (Black Box TL115A) and tried to make this work
with no luck. If I connect my computer's output directly to the KXPA100
serial out cable, it works fine. If I connect the ATU to the KXPA100 serial
out, it works fine. If I put the splitter in place, even if I only just
connect the computer, I cannot communicate with the KXPA100. Same re: the
ATU. Connecting both does not work either. I did get these devices off eBay
(I was shipped two, actually) but neither appears to work - not sure if
this is faulty adapters or if this mechanism just doesn't work in general.
I only spent $10 on them, so it's no big loss, but I'd sure hate to go
spend $80 on the BCE model to have the same results.

Is there a way to make this work without software, so I can still control
the KX3/KXPA100/PX3 via the computer, but the ATU can read frequency data?
I'm considering one of those Y-splitters (one male to two female?) but I'm
worried that this will prevent me from being able to use the computer to
change the frequency on the radio.

I'm still trying to solve this outside of a software solution, that's my
last resort if I can't make something work in hardware.

Thank you all again,
David


On Fri, Jan 20, 2017 at 8:11 AM, Joe Subich, W4TV <lists at subich.com> wrote:

> On 1/19/2017 10:53 PM, David Orman wrote:
>
>> I need an additional RS232 output in addition to the connection
>>>> to the PC for an external device that needs to track the vfo
>>>> frequency of the KX3. I'd like to have the PC able to track what
>>>> frequency/control what frequency my radio is tuned to, and at the
>>>> same time have my external device also tracking the frequency the
>>>> KX3 is tuned to.
>>>>
>>>
> David,
>
> What is the external device?  Does it need to poll the KX3 or is it
> satisfied by seeing the IF; and/or FA; responses to the logging
> software?
>
> RS-232 is a point to point protocol and does not allow for multiple
> active transmitters at the same time. However, in some cases one
> can attach a second "receive only" device in parallel.  The typical
> connection is shown in the SteppIR "Y cable" schematic that I have
> sent to you directly (ignore the jumper between pins 7 and 9 as that
> is SteppIR specific).
>
> If both the computer and hardware device must poll independently,
> you might be able to get away with a "Modem Data Splitter" like
> one of these from B&B Electronics: http://www.bb-elec.com/Product
> s/Serial-Connectivity/Serial-Data-Tools-Adapters/Port-Splitters.aspx>
> but you need to be careful that both the logger and hardware device
> do not send data to the KX3 at the same time since the modem data
> splitter is passive (diode isolation) and the data will be corrupted
> if both devices transmit at the same time.
>
> 73,
>
>    ... Joe, W4TV
>
>