01-21-2004 04:59 AM - edited 03-13-2019 03:26 AM
Hi all,
I have CP-7920 Wireless IP-Phones connected to an Access-Point 1200. The Problem is during a call the called party hears a continous background hissing noise. I found nothing how to turn this off. The wireless connection in principle is regarding to signal quality ok. The 7920 is running the latest Firmware 7920-sccp.1-0-6 and the AP 1200 is running the latest IOS 122-13.JA1. I´ve as well configured QoS on the WLAN.
What could be the solution for this problem?
Thanks in advance,
Gerald
01-27-2004 01:53 PM
Try tuning the output attenuation.
02-04-2004 11:57 AM
I´ve tried tuning the output attenuation of the Wireless Phone but it does not really help.
But anyway, thanks
01-29-2004 01:52 PM
I'm getting the same problem with my customer but with AP 1100.
Did you get more news since your post ?
02-04-2004 11:58 AM
unfortunately I got not more news since my post.
I found out that it is not related to the AP because I´ve also experienced the same problems with a NetGear AP.
02-16-2004 03:41 AM
The problem is related to an issue in the Firmware of the 7920 in conjunction with G711 a-law.
CSCed01562:
Static noise can be heard on the Cisco Wireless IP Phone 7920 when the phone is using a-law companding.
Workaround: Use u-law companding, if possible. If that is not possible, there is no workaround
After changing the codec to G711 µ-law the problems has been solved.
02-16-2004 06:33 AM
I have done a simple test to verify if this issue was due to this bug. But simply when you call an other IP Phone (7960) from the 7920 IP Phone, there is a background noise heared on the 2 IP Phones (7960 & 7920) during the conversation.
The codecs tested were G729 and G711 ulaw.
02-17-2004 06:44 AM
It seem that you have a different issue.
My problem was a static background noise not on the 7920 but on the other end. Whereas there was no difference whether it was a call within the IPT environment or to the PSTN.
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