Athanasios Silis wrote:
  You see I have the following midi port , which I can
see from "aplaymidi"
 through port (14:0)
  aplaymidi -l 
  Port    Client name
Port name
  14:0    Midi Through                     Midi Through Port-0
 however in amidi -l does not show this port.
 I understand client:14 is a software port, but it registers with jack
 properly - through the use of a2jmidid (shows up both in "ALSA" and
"JACK"
 tabs in qjackctl connections window) and with aplaymidi.
 how can I send data to this port ? 
Load the snd-virmidi driver.
(The "Through" port loops back all received data back to itself (to its
output).  The snd-virmidi ports route the data from the rawMIDI port to
the sequencer port, and vice versa.)
Regards,
Clemens