What do you mean D is dimension if all C048-x-xx, C096-x-xx, C264-x-xx, C520-x-xx are 'Dimension'? Or I don't understand something in between the lines?
And C you mean communications which is PSTN line? Or? (I have attached picture that states that D is with PSTN dialler). And so can't find any other controllers that would be listed on Honeywell website with C, only the documentation page http://www.honeywellvideosystems.com/download/Galaxy/EN_GaTechDocsPanels.htm