Hi Mike:
That's odd. An OBi should generate a dial tone on any working telephone that you plug into its phone port(s), even if there is no internet connection. No fiddling with DMZ nor opening ports is required; in fact, you should remove all those modifications for the sake of security.
Is this a brand new OBi, purchased from an authorized retailer (i.e. Amazon, Newegg, Fry's)?
Try this: Unplug all the cables from the OBi (power, Ethernet and phones). Find the small recessed reset switch on the bottom of the OBi (a hole in the middle of a small raised circle). It takes some dexterity to do this: use a straightened paper clip. Gently depress and hold down the reset switch while plugging in only the power cord. Wait at least 10 seconds, until the power LED flashes. Release the paper clip. Let the device sit there for a few minutes, until it completes the factory configuration restoration, and the LEDs stabilize. The left LED (power) should be lit steady.
Now, plug in only one RJ-11 telephone cord, into the Phone 1 jack. Do not plug in the Ethernet cable yet. Do you get a dial tone? If not, try a different phone and a different telephone cord.
Note that the OBi 202's two phone jacks are wired like this:
Phone 1: RJ-14, four conductor jack. Line 1 is on the center two pins, and Line 2 is on the outer two pins. This is designed for use with a four-conductor, RJ-14 cord, with four gold pins on each plug, connected to a two-line telephone.
Phone 2: RJ-11, two-conductor jack. Line 2 is on the center two pins (the Phone 2 jack's inner two pins are simply jumpered over to the outer two connectors on the Phone 1 jack). This would be used if you had two separate 1-line phones (plug one single-line phone into Phone 1, and plug the other phone into Phone 2.
