The J-41 model was used in the TG-5 and TG-5A sets.
The J-41 key.
This is a scarce key since it was used on only one device, the TG-5 (and TG-5A, TG-5B) field signal telegraph set.
It has both normally open (front) and closed (rear) contacts, and has a third binding post near the tension adjustment screw.
The wire terminals are: Front right, front (NO) anvil contact. Rear left, back (NC) contact. Rear right, main lever (common).
This is to prevent dust particles from creeping underneath the rear contact, separating the contacts and thereby opening the line"
(as stated in Technical Manual TM11-351, issued 1943).
Vergleich J-37 und J-41-A
A special version of the J-37, called a J-41-A is furnished with an extra terminal on the right side.
