On 07/12/2022 15:21, Neels Hofmeyr wrote:
So far I always have two physical phones camped on a physical BTS to test
voice. Speak into each handset and hear if the other plays it back. It involves
a lot of plugging and SIM card and android settings / flight mode.
I used some setup a long time ago with the various virtual components,
but it was mainly for SMS, I remember I had some problems with paging
that was a show stopper, and I never looked at it again.
It would be great to have a simple echo service. Adding osmo-sip-connector and
kamailio to osmo-msc is fairly easy, we have example config in osmo-dev.git.
But I don't know how to do an actual echo with a delay of two seconds.
Well, You can add some delay with rtp jitter-buffer on the bts.
It accepts up to 10 seconds, but stops working for me with smaller
values than that, I start to get:
DLMIB DEBUG <0014> ../../git/src/trau/osmo_ortp.c:205
osmo_rtp_socket_poll(209920): No message received
DLMIB NOTICE <0014> ../../git/src/trau/osmo_ortp.c:0 rtp_putq: Queue is
full. Discarding message with ts=2870320
but 1500 works and gives you enough delay to be able to say something
and hear it back.
I also find basically all of the PBX config daunting and near impossible to
understand. Maybe someone who knows which PBX provides an echo service can
write up a wiki page on osmocom.org to describe it?
What did you think of
https://osmocom.org/projects/cellular-infrastructure/wiki/Simple_Echo_Server
?
I don't see that the SEMS echo app has a param for buffer size,
unfortunately, I don't think the delay time is variable. If I find a
way, I'll add it to the wiki page.
K/
