Can anyone identify this Simplex/Grinnell PA/VA?

Hello everyone! Back in April 2022, my father was able to get this Simplex PA/VA from an airport he worked at during the installation and testing of a brand new 4100ES system. Haven’t been able to figure out what key it takes, what model it is, how old it is, and haven’t found any wiring/installation manuals either. Please see pictures below.

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I take it you’ve tried the regular Simplex B key / CAT 30? I see there’s a MCM501 model number, but I too am unable to find any documentation on it in particular.

Have you tried a “b” key in the lock

Per this datasheet, it looks like this was designed to be used with a Grinnell Autocall TFX-series panel:

Master Communications Modules (MCM-500) provide a microphone with a push-to-talk switch for broadcasting live instructions to selected zones. A master telephone for two-way firefighters telephone communications is provided as an option.

I unfortunately don’t know which type of key was used on Grinnell Autocall products.

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Oh wow, hey Zach!

Yes, I tried the B key to no avail. However, I was able to pick the lock using paperclips and remove it. Will keep you posted on updates if I find anything. Sorry for the late reply, I reached my daily limit.

I might sell the PAVA, if you are interested please let me know!


Wow, thanks! I picked the lock and removed it. I do know there was an old autocall panel next to the 4100ES. It still works and provides protection for the parking garage! This PAVA has the telephone.

Yes, see reply to zach

Have you found Ana datasheets for specifically the MCM-500? I have absolutely no clue how to wire it.

Try an ll805 key. Someone said that there grinnel pull station takes that key

I unfortunately didn’t come across anything else that was relevant. Grinnell Autocall datasheets will likely be harder to find as I believe the product line was phased out in the early 2000s.

That’s a hell of a find on the datasheet!

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Oh damn, hi Zach. I was able to pick the lock and open it!

Have you found a key for that thing yet??

Nope! I picked it and removed the lock.