Noise on A1200 while incoming call

Please refer this link:
http://wiki.openvox.cn/index.php/Troubleshooting_of_Analog_cards#Q12.2C_Sound_Quality_Problems_with_Analog_cards

Thanks for link.
Unfortunately, that's not my problem. I'm getting the noise only when other phones ring, and everything is ok in any other cases. No hum or noise from HDs or other stuff, no described IRQ problems. As I understand, the line voltage rises when incoming call comes and phones rings, and it might be cause for that damned noise. Somehow ring signal interferes with already connected lines. Any ideas?

I doubt the noise is because the bad wiring of telephone line. could you try only connect 1 line of a group? in this case the noise should disappear.

another question, is what kind of pc power supply you are using? does it have enough power?

Hi!

Unfortunately, I had no ability to try your your advice yet, but I'll try in several days. The power unit of my PC provides 550 W as listed, for two A1200P boards fully equipped with FXS modules. Is it enough?

So, no one answered my another question: the main A1200 board has small holes under every module, and the modules has the same. Looks like there must be some grounding connection between them, but I never found anything about this in manual. What's the purpose of these holes?

hello:
to make sure the FXS modules and the main module is well connected, the hole is designed to screw on the main board. it is not for ground connection.
regards!
James.zhu

Yes I had the same problem, weird noises when a new call was detected by the PBX, just one big beep... I changed this to use Queues instead of Ring Groups.. then made all extensions always logged..

Still have some problems with low sound in some calls, tried the phones directly connected to the pstn trunk and no problems..

I changed the values of rx and tx but still happening for some calls.