Direwolf using wrong UDRC channel when selecting -x option Send Xmit level calibration tones

[f6bvp]

Hi,

I am using Raspberry Pi 3 with Compass Linux distro and NW digital Radio
UDRC-II modem connected to a YAESU FT7900E transceiver.
Like many TRX Yaesu radio has a rear panel Mini Din 6 Data plug designed
for connecting a TNC for 1200 or 9600 packet.
I connected YAESU to UDRC with a standard din 6 cable and configured
both channels 0 and 1 with PTT gpio 12 and 23 respectively as documented
on NW digital Radio UDRC documentation : UDRC modem channel 0 is on HD15 plug, channel 1
is on din 6 plug.
In such configuration Direwolf is doing well listening and digipeating
APRS beacons.

In order to perform audio level tests I used measure.deviate script with
parameter -c din6.
Again, measure.deviate script performed well, sending sound signal from
generated wav file and pushing PTT via gpio 23.

Above results illustrate that din6 cable hardware connections are fine.

However when I using Direwolf calibration test command line option -x then PTT is not activated.
I discovered that interverting gpio 12 and gpio 23 makes PTT work, meaning that with -x option channel 0 PTT needs to be 23.
However, while Yaesu radio transmit mode is activated by PTT, there is no modulation i.e. no calibration tone sent !
After a lot of trials I found that one option could make UDRC modem send calibration tones.
Selecting command line parameter -n to value 1 makes it happen.
Conclusion : while in normal mode Direwolf is working with UDRC modem for output on plug din6, it does not configure itself correctly when choosing test option -x.

Reading document (https://nw-digital-radio.groups.io/g/udrc/wiki/Creating-Virtual-Sound-Cards-for-the-UDRC%E2%84%A2) I decided to simplify configuration file to one device even if UDRC modem is a dual channels audio card.
I arrived to the following configuration file :
ADEVICE plughw:CARD=udrc,DEV=0
ARATE 48000
ACHANNELS 1
#Channel 0 is on din6
CHANNEL 0
MYCALL F6BVP-5
MODEM 1200
#PTT GPIO 23 is for din6
PTT GPIO 23
AGWPORT 8000
KISSPORT 8001
This configuration makes Direwolf happy sending calibration tones via Yaesu TRX connected to din6 plug !
In that case gpio 23 is correctly activating PTT via din6 and tone signals are send through CHANNEL 0 while NW digital Radio documentation says that din6 is Port 1 and I assume that port 1 is Channel 1 for this is what works correctly in Direwolf normal mode.

Let me ask a question about menu :
Usage: direwolf [options] [ - | stdin | UDP:nnnn ]
Options:
-c fname Configuration file name.
-l logdir Directory name for log files. Use . for current.
-r n Audio sample rate, per sec.
-n n Number of audio channels, 1 or 2.

Does -n n means "Audio channel number, 1 or 2"
or does it means "Number of audio channels, 1 or 2)"
When setting -n 1 Direwolf displays :
...
Audio device for both receive and transmit: plughw:CARD=udrc,DEV=0
(channel 0)
while without -n option and ACHANNELS 2 it displays (channels 0 & 1)

Final remark : in any of above cases (ACHANNELS 1 or 2 and normal mode or -x mode), a calibration signal flows out of HD15 pin 9 as verified with an oscilloscope whenever a single channel is set or both.

Bernard, f6bvp