[Boatanchors] Electronic TR Switch?

[StephenTetorka at cs.com]

Hi all:

Picked up a nice little homebrew electronic TR switch.
Now I need to know how it works..and would appreciate any info.

Here are some details:
Made in 1976
Uses MC1741CP chip and two transistors, one being 2N2222.
Has sensitivity and delay controls on front panel
Back panel has 4 pin connector for Mute and +12.5, jacks for H.P. 
( headphones?) " ST " and "R" and BNC's for Rcvr, Ant and Trans.

Thanks,
Steve
WA2TAK