|Western Electric 558 2-Line --
Two-line wall w/ signal key, exclusion, control leads and A-lead control for 1A2.
Marked 558F 6-76.
|Exclusion key mounts in the top right corner.
Plunger is in the normal position. Pull up to exclude.
|Top view shows the arm that resets the switch when the
handset goes on-hook.
|Side view. The bulge on the left of the plunger
activates the switch.
The narrow section to the right of the switch engages the reset arm.
The switch is loosely coupled to the L-bracket mounting arm, so it will self-position in the hole in the housing without putting excessive stress on the hole in the plastic.
|Back view shows the two mounting rivets on the upper left.