[Ekiga-list] Difference between 500 and 520 echoes

[dima minignu minidns net (Dima Sorkin)]

Hi.
  Ekiga 3.2.7 at Debian/SID (powerpc).

  When I call 500 at ekiga dot net, I hear silence, and in fact, the numbers at the bottom of a window show that no audio is received from the ekiga.net server. Video is ok, after 20 sec my cam is echoed to me back.

  On the other hand, when I use the 520 at ekiga dot net, it returns call to me, and then audio is just fine. Other audio echo services (4444 at sip2sip dot info) work fine.

  With Twinkle on the same machine the audio echo from 500 at ekiga is fine.

  What can be the reason that with Ekiga I get no audio echo from 500 ?

Thanks, regards,
  Dima