The 1.9-mf capacitor in Telephone EE-8,
or the 2.0-mf capacitor in Telephones EE-8-A and EE-8-B, is in series
with the ringer when the screw switch is in the CB position. This
capacitor prevents direct current from biasing the ringer and also pre
vents the ringer from interfering with d-c signaling or supervision when
the telephone is connected to a common battery system. The capacitor is
short-circuited when the screw switch is turned to the LB position.
The transmission loss through the ringer, or the ringer and the
capacitor in series, and the holding coil is negligible because of the high
impedance to voice-frequency currents of these elements.