The frequencies have been used for analog and digital cell service. Almost sounds like a classic bag phone base. Ouch, the memories... Here's one on ebay:
<img src="http://i11.ebayimg.com/03/i/03/0f/e5/a0_1_b.JPG">
What are the device dimensions? Can you post a picture? There are enough geeks around here... One of us has probably seen it before.