Line Quality problem with Cox/Vonage

I have had line quality issue for a very long time and want to troubleshoot them. Many calls to Vonage Support have made varrious tweaks and upgrades and most recently changed motorola voice router to a Linksys. Here is configuration:

COX HSI ----> Cable Modem ---->Voice Router--->Wireless 802.11g ......................................! ......................................! ................................900 Mhz cordless

Speeds on Vonage Line Test

Download 1,851,576 bps Upload 452,936 bps QOS 56% RTT 90 ms MaxPause 131 ms

My Results (late night) Download 1,743,976 bps Upload 459,856 bps QOS 70% RTT 90 ms MaxPause 140 ms

Cable Modem = SMC8002CM Voice Router = Linksys RT31P2 Wireless Router = Motorola WR850G

900 mhz Cordless phone = VTech VT2910C

95% of my calls are made while in front of my laptop with wireless notebook card installed.

I really do not have any complaints with my COX HSI connection, always fast downloads. I really have problems with the phone quality during peak inet traffic (mornings and late afternoons/early evening) That said, that is just when it is worse. I have problems almost every call and I am on the phone a lot, as I work from home.

I have recently done some pingplots and do not show much packet loss, except during the peak times. Here is my ping plot

. I did not run long enough to catch the morning, but I am sure it would be like the late afternoon. Not sure if I ran it right. Just had it ping the pingplotter website. I tried to ping the Vonage site and had similar results, but the last ping at Vonage was 100% packet loss at all times.

How about my phone, could any interference be going on? I dont have a hardwire to check it out.

I have to solve this problem, any help would be greatly appreciated.

Craig