I will fly over and install one for less than that
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The v2 is a very old unit, the UK version only went to 6 and v 2 was about 12 years ago. I say they would be very close to the version. what model phone is on it, does it have the wheel at the bottom right of phone, if yes does it control scrolling of speed dial or only volume control. is the 2 on the main control unit or on a module on the front of the system. could mean nothing at all.
The moh is in the 990 programing and is binary ( 1's and 0's)
as for ringing you could set up a hunt group or just put delay ring on those extensions and they will ring after set amount of rings with the first phone