No busy signal

Hello i have an issue with Yealinks (Yealink SIP-T22P FM )
our compeny have only 3 yealinks and the rest is Grandstream.

for some reasone the Yealinks does not give us a busy signal if im calling to
a busy phone number (like somone is allready on the phone) or if there is a music instad of a ring tone in some numbers we do not hear them.

we hear a regular dial tone.

can you please help?
somone reccomended me to change Early media setting so i did from disable to enable and it did not help.

any idias?


Usually you use Progress() before dial, in order to get early media audio.


thanks for the replay.
but, if its the dial plan why is it happend only on the yealinks and not the grandstreams?


The problem is that, sometimes, it is not an easy task for a UAC to
know whether it will be receiving early media or it should generate
local ringing. A UAS can send early media without using reliable
provisional responses (very simple UASs do that) or it can send an
answer in a reliable provisional response without any intention of
sending early media (this is the case when preconditions are used).
Therefore, by only looking at the SIP signalling, a UAC cannot be
sure whether or not there will be early media for a particular
session. The UAC needs to check if media packets are arriving at a
given moment.

Upgrading to the latest Version has solved it.