(3) After the AC signal passes through the C-2298 MONITOR switch
(Figure 16), its strength is increased or decreased by the volume control.
The signal then passes to pin B of J802 or J803 and then to the audio
accessory phone element or to pin E of J802 or J803 and then to a speaker
(LS-454). (Trace this circuit on your system diagram.)
Figure 16. Listen circuit (AC signal) from MONITOR switch through
volume control to pins B and E of J802 or J803.