[Boatanchors] What was "test unit" "I-85-D" made for the Signal Corps - US Army by Western E

[COURYHOUSE at aol.com]

What was "test unit"  "I-85-D" made for the Signal Corps -  US  Army by 
Western Electric used for?
An info appreciated!
Many Thanks  Ed#  _www.smecc.org_ (http://www.smecc.org/)  
Please help support this email list:  http://www.qsl.net/donate.html