hiccups in voice quality

[mj56gt]

I'm using an OBi110 with GV through a wireless N router and Cat 5e cables, and notice that there is about one hiccup (silence lasting for ~1 sec) per minute at average during calls. Internet speed test indicates that the download/upload speed is about 24/4.5 Mbps. What could be the cause(s) for such hiccups?

Not sure if it's related. I just checked my cable modem error logs, and there are a lot of stuff like:

SYNC Timing Synchronization failure - Loss of Sync
No Ranging Response received - T3 time-out
Cable Modem Reboot due to T4 timeout
Ranging Request Retries exhausted
Unicast Maintenance Ranging attempted - No response - Retries exhausted

[Shale]

Could be caused by
Lost packets due to internet connection having problems locally.
Lost packets due to internet connection having problems not locally.
Competing traffic from other applications consuming bandwidth.

Test for lost packets to a server that returns pings. You may be able to use your SIP server as the target.

Turn off all of you computers, and try test calls. Did the problem disappear?

[mj56gt]

Could be caused by
Lost packets due to internet connection having problems locally.
Lost packets due to internet connection having problems not locally.
Competing traffic from other applications consuming bandwidth.

Test for lost packets to a server that returns pings. You may be able to use your SIP server as the target.

Turn off all of you computers, and try test calls. Did the problem disappear?

Thanks for the suggestions. The hiccups happen usually when there are no other electronic devices on the network, but I'll try to do more diagnosis about this. Thanks again for your help!