Simplex Adapter Plates

Hi everyone:

I was wondering if anyone knows what the model numbers are for the following Simplex adapter plates and and where these plates can be found. These are plates that would fit on a 2975-9145 back box.

The plates that you can install the 4903-9101 series plates onto to fit the unit on the 2975-9145 back box.

The Simplex retrofit plates that allow a normal double gang backbox compatible signal (i.e. TrueAlert, Wheelock RSS and other legacy devices from Wheelock) onto the 2975-9145 backbox (like the ones that they use during retrofits).

For reference, the 2975-9145 backbox was originally for the 2903 series and is compatible with modern signals if you use these retrofit plates. The problem is, you can’t install any other signal onto these back boxes without these retrofit plates which seem sort of hard to find on eBay or anywhere, actually. You can see one of these plates mounted onto a 2975-9145 in my School Fire Drill video on my YT channel for reference with a Wheelock HSR on it.

4903-9101 series plates - 4905-9903 Adapter Plate

TrueAlerts/4" square devices - 4905-9931 Adapter Plate

This document should be helpful to you: <LINK_TEXT text=“ … 5-0008.pdf”></LINK_TEXT>

Thanks! I might purchase one of these in the future!