We had an odd problem (seems to be common for me) tonight after my wife checked VM. She hung up after listening to all of the messages and tried to dial, but there was no dial tone. We waited a few more minutes and I checked the HT502 and it showed registered and up. I finally rebooted the ATA and everything was working again. I've never seen so many problems with an ATA until I got this Grandstream box. And yes, the HT502 is connected directly to the cable modem.