Strange outbound sounds

There is no problem when calling through the smartphone wireless network, but when calling through the pstn phone, the sound is strange.

PC softphone <-> asterisk <-> Smartphone : OK
PC softphone ← asterisk ← Smartphone : OK
PC softphone → asterisk → Smartphone: problem occurs

No sound from the PC softphone side
There is a lot of noise in the PSTN wired network.

If NAT-related settings are modified, communication itself will be problematic.

It seems to be a problem with the rtp option or codec. Has anyone experienced a problem with it? Thank you for your solution.

You’ll need to provide all the information for anyone to even being to help … Asterisk version, config files, network setup, etc, etc.

PSTN is always ulaw/alaw.

In addition to the other information, you need to explain what you mean by noise.

Real noise indicates a hardware problem, on the non-VoIP part of the circuit.

It sounds very strange. It sounds like a mechanical sound.

[general]
allowoverlap=no
alwaysauthreject=yes flag
directrtpsetup=yes
rtcachefriends=yes
rtupdate=yes
qualify=yes
allowguest=no
match_auth_username=yes
callcounter=yes
trustrpid=no
sendrpid=yes
; – connection (nat …) ----------------
directmedia=no
comedia=yes
force_rport=yes
canreinvite=no
defaultexpiry=60
minexpiry=30
maxexpiry=120
; – dtmf & rtp ----------------
dtmf_mode=auto
progressinband=yes
dialtone_detect=yes
relaxdtmf=yes
rfc2833compensate=no
rtp_symmetric=yes
rtcp_mux=no
use_avpf=no
ice_support=yes

[1000]
type = endpoint
context = default
transport = transport-tcp
dtmf_mode = auto
disallow = all
allow = ulaw
allow = ilbc
allow = alaw
allow = gsm
rewrite_contact = yes
trust_id_inbound = no
send_rpid = yes
inband_progress = yes
language = en
auth = 1000
outbound_auth = 1000
aors = 1000

This is the “pjsip.conf” configuration file.

That’s not an description I’ve heard before, but I suspect it means distortion, not noise.