Folks, this customer has 13 trunks - 8 DAHDI and 5 SIP. The sip trunks run through a Grandstream Gateway and add another three POTS to the system. The routes are divided as inbound 8 and 5 outbound. The 5 SIP are the outbound. Some of the outbound calls have intermittent problems with static. I have checked all the trunks for cable/telco trouble. They seem to be ok. Any suggestions please?
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UCX 50 - Static on inbound calls.
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Hey Random 192, thanks for the response! I monitored the POTS lines for more than three hours yesterday and heard nothing. As a guess though, I believe the noise is coming from the UCX itself, because I had the SIP/Gransstream trunks tured off for more than a week. The problem persists.
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Oh good this is easy then. Your digital station module is the likely problem. With IP its a very binary connection it either works or it doesn't. So you can get call path drops and stutter associated with packet jitter but "static" is generally an analog/digital issue. Do you have a spare DSM module to swap out?
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curlycord
Programmer
A nosy curious question...
If the UCx handles SIP Trunks then why is there a Grandstream in the way?
Did you verify the analog ports on the Grandstream are clean? you can use any analog set to test.
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If the UCx handles SIP Trunks then why is there a Grandstream in the way?
Did you verify the analog ports on the Grandstream are clean? you can use any analog set to test.
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Just curious...
The thread started with an analog trunk problem. Unless I missed something, the suggested "solution" appears to be to go to old DSM hardware. If the problem is indeed with analog trunks, why would anyone expect the problem to go away after a change of the digital set interface device?
In my opinion, there is a simple test to determine if the problem is with the analog trunks or the digital set interface device. When you make internal calls (extension to extension), analog trunks are not used at all. Therefore, if there are no issues with static on internal calls, the problem is not the digital set interface device.
If there is static on internal calls, you can look at the configuration of the digital set interface device / the UCx system. If the digital phones (the DSM16) are not collocated with the UCx system, you should make sure that the jitter buffer is enabled on the Nortel Settings page (packet loss due to a remote jittery network connection could sound like static).
If internal calls are okay, but external calls over the analog trunks exhibit the problem, you should focus on the analog trunks. First, you should make sure that the ucx_ectune script is executed while the 8 trunks are connected (you should follow the E-MetroTel documentation for setting up analog trunks). Second, it is important to understand what the users call "static". The type of impairment could provide an indication where the problem might be. My recommendation would be to record a couple of such calls and send the recordings to E-MetroTel support.
The thread started with an analog trunk problem. Unless I missed something, the suggested "solution" appears to be to go to old DSM hardware. If the problem is indeed with analog trunks, why would anyone expect the problem to go away after a change of the digital set interface device?
In my opinion, there is a simple test to determine if the problem is with the analog trunks or the digital set interface device. When you make internal calls (extension to extension), analog trunks are not used at all. Therefore, if there are no issues with static on internal calls, the problem is not the digital set interface device.
If there is static on internal calls, you can look at the configuration of the digital set interface device / the UCx system. If the digital phones (the DSM16) are not collocated with the UCx system, you should make sure that the jitter buffer is enabled on the Nortel Settings page (packet loss due to a remote jittery network connection could sound like static).
If internal calls are okay, but external calls over the analog trunks exhibit the problem, you should focus on the analog trunks. First, you should make sure that the ucx_ectune script is executed while the 8 trunks are connected (you should follow the E-MetroTel documentation for setting up analog trunks). Second, it is important to understand what the users call "static". The type of impairment could provide an indication where the problem might be. My recommendation would be to record a couple of such calls and send the recordings to E-MetroTel support.
getsomesun1
Technical User
I agree with ucxguy. Follow these instructions for ec_tune to optimize your analog trunks.
This is late to the party, but thought worth adding - have seen on 2 different Grandstream FXO boxes where the caller can hear a little bit of static, or hiss on the line when they talk. It's somewhat faint, but it is there. If you clip a butt set on the line it sounds clean, only through the phone you can hear it. These were 2 different boxes at 2 different sites.
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