Unusual Kellogg Red Bar

[LarryInMichigan]

I spoke today with someone who advertised a number of phones for sale on-line.  One of the phones is a Kellogg Red bar with a strange knob or button sticking out of the side.  He sent me a picture of the thing, and I was wondering if anyone had any idea of what it is.  I only have this one photo, and the seller is about 1,000 miles away from here.  The phone is for sale if anyone is interested.  I told the seller that I could post information about his phones on the forum in case there was any interest in his phones.  I am in the process of buying two of them now.

Larry

[rdelius]

Possible hook latch 2 step switch to listen in on a party line to see if the line is in use before going all the way off hook. The transmitter is not in the circuit unless all the way off hook.Other manufactures such as SC offered this .
Robby