I am not clear on what you are asking. Both domes use the same 160mm x 160mm bolt patterns with mounting bolts coming into the bottom of the dome. The scanner cable for the 1815 is a new type that uses a pigtail cable that prevents the need to open the dome and insert the connections to the circuit boards. With the 1815, you normally bolt it down and then just plug in the scanner cable to the pigtail and weatherproof it.