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Audio problems on phones (t23g i t42s)
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bob_1921 Offline
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Post: #3
RE: Audio problems on phones (t23g i t42s)
(12-02-2020 12:43 AM)complex1 Wrote:  
(12-01-2020 12:10 AM)bob_1921 Wrote:  Hi,
I have one interesting situation with a series of t23s and t42s phones. Before I describe the problem brief introduction: I have installed over a hundred phone combination t23g i t42s series, on some maybe ten cases the phones are behaving strangely. During the day on some maybe ten phones, happen that three or four calls have difficulties, the audio does not reach the phone. (pbx configuration is ok, also network configuration is ok), when I go to the location where the phone is and I test everything is fine.

The hardware part of the phone is fine, as well as the configuration of the pbx and voip network, it is interesting that when I replace the phone with a new one, the problem disappears and I put the phone that caused the problem in another location and there is no problems, phone work fine ...
I've researched a bit and seen I don't know if I'm right that yealnik requires that RTP ports be set in the range of 11780 to 11800, and that's the configuration on all phones i have instaled.

What do you think, Is this the reason for the difficulty white audio on some phone, because I put this range of RTP port, same on all phones. Do I need to expand the range of RTP ports on the phone and after how many configured phones should it do (Now the range of RTP ports is set to 11780 11800).


A possible SIP ALG setting in the router can cause the issue, please disable it.
If you use more than one device in the office and the PBX is in the cloud, possible you need to setup each device its own local SIP port and RTP port range.
Phone 1, local SIP port: 5062, local RTP port 14000-14019
Phone 2, local SIP port: 5064, local RTP port 14020-14039
Phone 3, local SIP port: 5066, local RTP port 14040-14059
and so one...
Also each device need to have it own fixed LAN IP address so the PBX can "find" the phone.

Hope this will help.

Thanks for your reply. I will tell to the network administrator your suggestion aboute disable SIP ALG setting.

PBX is not the cloud tip, our pbx in the firm is a hybrid (sip, isdn, analog), we have a combination in the company isdn, sip, and analog phones and lately we are throwing out isdn and inserting sip phones and there are all yealnik. Every sip phone gets its ip address via dhcp, at first I thought that the network connection is lost but no, when a problem occurs yealnik does not lose the network only the audio is not played properly, and this situation is not common ... it's a bit of a strange problem and irritates users, for the reason that it happens two or three times during the day, but it is difficult to catch the problem in real time ...

I thought it might be related to the RTP ports on the phone (because i put RTP ports on all phone, range 11780 11800), I don't think it's a hardware problem, because the phone works in another office, also when I replace the second or third yealnik phone, problems stop happening in that office... but again, now when I read my question again aboute RTP I know maybe it was a stupid question aboute RTP ports because the other phone works Smile ... ...
(This post was last modified: 12-02-2020 04:47 AM by bob_1921.)
12-02-2020 04:46 AM
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RE: Audio problems on phones (t23g i t42s) - bob_1921 - 12-02-2020 04:46 AM

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