voip device connected to Nighthawk AC2400 router connected to Nighthawk CM1200 outer

[grothen]

Can I still use a polyom obi200 voip device that is connected to this router if the modem says not compatabile with bundled voice services?

[plemans]

Yes you can use that device. That device is its own voip that you buy service for. The "not compatible" you're speaking of is the ISP's own voice service. Not 3rd party voip providers.