ringer booster

[Alex G. Bell]

Does anyone have experience with the earlier Viking RG-4 booster?  It's about half the price of the RG-10 and gives an equivalent of 4 REN compared to 12 REN on the larger unit.  Much smaller in physical size too.  The specs however state that it's not rotary compatible - odd when the phone and line connections are screw terminals.   Don't quite understand how a phone dials out would affect the incoming ring signal.  Any thoughts from the technocrats here.

I've found Viking tech support to be very friendly and helpful.  Rather than speculating I suggest posing the question to them.