I am on Kubuntu 20.04, I have a usb-connected fax modem, and I installed the following packages:
efax
efax-gtk
sl-modem-daemon
I ran: sudo gpasswd --add shmuel dialout
The modem is identified by VirtualBox as: Conexant System, Inc. USB HSF Modem
When I send a fax I get this output:
Socket running on port 9900
efax-0.9a: 19:30:51 opened /dev/ttyS0
efax-0.9a: 19:30:58 sync: dropping DTR
efax-0.9a: 19:31:02 sync: sending escapes
efax-0.9a: 19:31:08 Error: sync: modem not responding
efax-0.9a: 19:31:08 failed page /home/shmuel/Downloads/poa.pdf.001
efax-0.9a: 19:31:08 finished - no response from modem
I ran
lsusb
And I saw this entry:
Bus 001 Device 010: ID 0572:1300 Conexant Systems (Rockwell), Inc. SoftK56 Data Fax Voice CARP
Settings of efax-gtk look like this
/dev
looks like this