multi line control unit??? what is this thing?

[RB]

can anyone give me the details on this piece?
wondering how it worked???
https://www.ebay.com/itm/Control-Unit-Multi-Line-Automatic-Electric-L7034/202668545173
?_trkparms=aid%3D1110012%26algo%3DSPLICE.SOIPOST%26ao%3D1%26asc%3D20190711095549%
26meid%3D6d9245d35fe04afaae0ba07ef5594b4e%26pid%3D100047%26rk%3D5%26rkt%3D12%26sd%
3D193681605233%26itm%3D202668545173%26pmt%3D0%26noa%3D1%26pg%3D2047675%26algv%
3DSellersOtherItemsV2&_trksid=p2047675.c100047.m2108
that is a lonnng link!

EDIT:  Link shortened to delete extraneous code and screen captures added.

[SUnset2]

That's a speakerphone control with microphone. There's a separate speaker that goes with it. (And an AE 80).

[paul-f]

There's a photo here (scroll down):

http://www.paul-f.com/speaker.htm

And tech info here:

https://www.telephonecollectors.info/index.php/search?q=TB%20701-89T

[RB]

Thanks