AE 21 or 42??

[Babybearjs]

I am restoring a AE #21 steel wall phone, and came across the info that the model numer could also be a #42 wall phone, the difference, the network... how strange. I just won the mouthpiece for the unit and now all I have left is to get the reciever... does anyone know why AE would have 2 seperate model numbers for the same type phone? fill me in on the history... I'm stumped!    John

[stub]

Babybearjs,
                 Go here and scroll down to download catalog 4055-C, on  pages. 18, 20, 37, 49, 50.  stub

                               
                                          http://tinyurl.com/4yutxg6

[Babybearjs]

thanks stub!