On a sunny day (Sat, 19 May 2018 11:31:11 +0000 (UTC)) it happened Martin
Gregorie  wrote in :

>On Sat, 19 May 2018 09:20:52 +0100, Dave Liquorice wrote:
>
>> On Fri, 18 May 2018 00:13:32 +0000 (UTC), Martin Gregorie wrote:
>>
>>> FWIW the target device is a Dittel KRT2 airband tranceiver.
>>
>> Have you checked that it setting the hardware handshake lines correctly?
>>
>There aren't any: the AXE027 USB-serial adapter uses a three wire
>connection terminated by a 3.5mm stereo jackplug. I know that's working
>correctly because using it lets a RaspberryPi interact with a PICAXE chip
>and I have checked that the connections between the KRT2 and a 3.5mm
>socket on my panel are good and connect the appropriate pin on the KTR2
>to the expected jack segment.
>
>This is why I asking about the adapter's compatiblity with async i/o
>managed by poll().

If you use the ptlrc commie-nuke-aid-ion program
just connect tx and rx together at the other end and type something,
should echo each character, confirms that your side is working.

Important is to get the BAUDRATE correct.
Often programs send some sort of hello message on powerup.
So see if anything happens in ptlrc when powering up that thing.
If it is unreadable try an other baudrate, and repeat.

Sometimes simply typing 'help' gets a response,
cracked a big expensive thing that way.

And finally, you DO use the right /dev/ttyUSBX ?
Type
 dmesg
insert the serial adaptor
type
 dmesg
again.
 it should show a new entry in /dev/ttyUSBX,
where X is the device number.

Or check with:
 ls -rtl /dev/ttyUSB*
crw-rw---- 1 root dialout 188, 1 May 13 13:25 /dev/ttyUSB1
crw-rw---- 1 root dialout 188, 0 May 19 08:13 /dev/ttyUSB0
crw-rw---- 1 root dialout 188, 2 May 19 14:37 /dev/ttyUSB2

Use last one

ptlrc -d /dev/ttyUSBx -b 19200???

type
help
??

--- SoupGate-Win32 v1.05