VS-GW1600v2-20G electrical noise

We just bought a pretty new gateway, with 5 gsm modules, connect him to my Asterisk Server.
And now we get electrical noise from sip channels, its heared only on client side, and we dont hear it on asterisk records.
When I try to troubleshot this problem - I connect from softphone to gateway and make routing from test client on sim-card, and still hear noise.
In connection from client to gateway I dont have any NAT or smtn, client and gateway is connected to the same switch (D-Link DES-1228-28/ME) in adjacent switch ports and in isolated vlan with static IP-s on both sides. And I have same problem on all gsm modules.
System information on Screenshot.

So what I can do to resolve this problem?

PS: sorry for bad english

Hello

Did you mean if you use software phone register directly to the gateway and make call out software phone still can hear noise ?
You can record the voice from the gateway to have a look ,Menu system---tools----voice record, select the port then start , make a call for test then stop the record , use Cool EditPro tools to check the record. Hope these info help you . By the way did you test the call with IP phone ?
If as you said you connect like this

client

---

asterisk server

---

gateway

---

carrier

client side hear noise , but asterisk server record not have , i think it not cuased by gateway ,do you agree ?

you can test like this

client A

---

asterisk server

---

client B

A call B . check if have nosie ?

Hope these info help you .

Best regards
upper

Hello, thanks for answer.

Yes when I connect to gateway without my Asterisk server I still hear noise.
I tried to record call with tool which you recomended and yes, I hear noise on this record.
About IP phones - we dont use it in our callcenter, so I has not it even for test (

About scheme - it is problem of gateway, in my opinion cause we have another sip trunks, and I back few sim cards to Huawei USB Dongles and I havent any noises in this type of connections.
When I test Client A -> Asterisk -> Client B - I dont hear any noises.

I was try to update Gateway to latests firmware (Software Version: 2.1.26) and still have this problem.

Hello

Is this device new ? You can add my skype upper.hua , we can talk there .

Yes, this device pretty new, we bought it at april, and trying to migrate on last week.
Add you in skype, thanks.