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4040+KWS300+Echo problem

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4040+KWS300+Echo problem



Currently using a KWS300 (PCS12 firmware) with 2x 4040 handsets.


When calling the remote party, the remote party hears echoing themselves with a few ms delay.


When exchanging the 4040 handsets for 5020 handsets the echo dissapears.


Also switching de KWS300 for a KWS600v3 and using the 4040 handsets again makes the echo (far end) dissapear.


Any help would be appreciated.


Kind regards.



Message 1 of 4

Re: 4040+KWS300+Echo problem

I also did some extra tests to try to solve this problem:


tested with 2x KWS300 PCS12 units


De far end echo is noticable when making calls internally (internal numbers)  from and to another KWS300 + 4040 handset, Grandstream 2000 or any other call to external fixed or mobile number.


X (far echo) KWS300 + 4040 handset via KPN ADSL using internal 3CX PABX V10

X (far echo) KWS300 + 4040 handset via Ziggo Cable using internal 3CX PABX V10

X (far echo) KWS300 + 4040 handset via LAN with internal  3CX PABX V10

X (far echo) KWS300 + 4040 handset via KPN ADSL with external VoIP provider (CallVoIP)

X (far echo) KWS300 + 4040 handset via Ziggo Cable with external VoIP provider (CallVoIP)


X (far echo) stays while changing KWS300 zoals codec priority U->A and upgrade firmware from PCS10 to PCS12

- (far echo) gets less while lowering handset volume from 4040  handset or changing mic gain from 8 to 0 using servicetool with  programming kit but never dissapears.


V (far echo) dissapears while using 5020 handset with KWS300 or a 4040 handset with a KWS600v3


Far echo never happens  between Grandstreams or analoge phones via Linksys ATA from Lan or Internet using internal phones or externals phones.


Please help......


Message 2 of 4
Polycom Employee & Community Manager

Re: 4040+KWS300+Echo problem

Hello Mirko,


welcome to the Polycom Community.


I had a quick discussion with one of our DECT Distributors earlier and we spoke about this post.


As far as he can remember it is pretty simple.


The KWS600v3 has a build in Echo Canceller

The 50xx Series has a build in Echo Canceller

The KWS300 does not have a build in Echo Canceller

The 40xx Series does not have a build in Echo Canceller


I would suggest you work with your KIRK Distributor to get this raised via Polycom KIRK support to confirm this.


Best Regards


Steffen Baier


Polycom Global Services

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Message 3 of 4

Re: 4040+KWS300+Echo problem

Hi Steffen, thanks for your reply.


My problem is though that I bought the hardware through a large German hardwareVOIP  supplier which only gave me the option to send the hardware back to them and have it RMAed to Polycom. Which I think is not the best solution since it can be tested with every KWS300 and a 4040 handset. At least i did so with 3 different KWS300 and 9 x 4040 and was able to reproduce this problem.


My Dutch supplier does not want to help since I did not follow a training for Polycom products with them.


I called Polycom German Support this morning and send them an email hoping that they are willing further to investigate.


Kind regards.



Message 4 of 4