Looking for info on Northern electric key systems

[5415551212]

Greetings all a while back I restored
a Northern Electric 6 Button 1A2 'Line Select Key Box':
https://www.classicrotaryphones.com/forum/index.php?topic=25437.msg250184#msg250184

And now I am finally getting around to wiring it up, an am curious if there is any documentation on these NE Key 1A2 systems?
I did a search on telephonecollectors.info but did not find much.

https://www.telephonecollectors.info/index.php/browse/document-repository/catalogs-manuals/all-catalogs-manuals/northern-electric

Thanks everyone!

[poplar1]

BSP 512-210-103 i6 in TCI Library shows WE 6040, 6041, 6050 and 6051.

[5415551212]

Hey thanks for the quick reply!! is a Northern Electric pretty much the same as western electric?
I am now studying the BSP 512-210-103 thanks!

I am planning to setup a key system with 4 lines and the 5th button wired as a signal button.

I was curious what all the screw terminals mean here is what I think is going on so far, its a hi res photo I took of the actual NE 6041QAA so I can make out what the screw terminals say;