Need to find matching connector

Hello all, I am looking to replace my wired fire alarms, but want to avoid changing the wiring

I am attaching pictures of an existing connectors. I need to find something that is like the yellow circled part in the second picture, then I can put together an ‘adapter’

But I have no idea how to look for it in the catalog

Thank you!

Welcome to the DigiKey tech forum. Looks like you have a 4 position connector with keying plug in one slot or it was made solid from the manufacturer. I wasn’t able to identify your connector in our list of similar parts. One of these may work if you can verify the pitch (center of contact to the center of the one next to it ) . You can narrow down the provided list once you verify the spacing and then you can look at body style and dimensions to further narrow down the options. These are 4 position connectors so you will want to fill the same hole to prevent plugging the connector in backwards.

Here are the options we have that are four-pin but with only three loaded. 4 Through Hole Headers, Male Pins | Rectangular Connectors | Electronic Components Distributor DigiKey you will need to measure the pitch (pin to pin spacing) on your connector to narrow it down further. Your other option if you cannot find one of these that will work is to buy a four-pin connector and just clip out the third pin with wire cutters.