On Sat, 19 May 2018 13:37:29 +0000, Jan Panteltje wrote:

> 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.
>
Thanks for that. With Rx and TX shorted together at the stereo jack the
AXE027 adapter cable is successfully echoing test strings back through
ptlrc  - so the cable is working. This works both on my RPi B (original
512KB version, Raspbian) and on my Lenovo T440 (Fedora 27).

However, that form of loopback isn't working with my code. so I've
probably got the serial port bit settings wrong, since the code works
correctly when talking to a target emulation program over a socket
session.

> Important is to get the BAUDRATE correct.
>
On your code it loopback works OK at both 4800 and 9600 baud.

> 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.
>
I'm still going to talk to the Dittel agents about the KRT2 signal levels.

In the meantime I'll review my serial port settings in comparison with
yours. This is a little puzzling, though because a while back I had the
port handler working well when driven by a glass teletype emulator
written in Java and using a real RS232 port connected to a system running
Microware's OS/9 at 9600 baud, so it looks as though I'm using port
options that worked with a full RS232 cable but not on a 3-wire link.

> And finally, you DO use the right /dev/ttyUSBX ?
>
Indeed, though its drivers need to be configured after connection to the
host and before attempting to connect to it - otherwise its simply not
there.


--
Martin    | martin at
Gregorie  | gregorie dot org

--- SoupGate-Win32 v1.05