marking signal S1. If this is the case a mark M1is present and in block 93 the microprocessor 42 produces a signal indicating the presence of a mark M1 on its output 94 for a predetermined time interval T6, which signal for example causes a light-emitting diode connected to the output ...
It is a three pin package the end of the 125 kHz receive amplifier chain, identified with the marking "RRN" and Q4 on the PCB (far left in photo below). Using the diode check function on a multimeter, it could be a bipolar NPN transistor, but I measure 0.8V from pin 1 to 2 and...
[Also in Division H4] Apparatus determining the service class for connection between subscribers of an automatic telephone exchange,wherein the connection is classified by a marking voltage having a predetermined phase derived from an n-phase system, and in which from the n-phase system a p-...
from being damaged. In addition, to reduce noises in the circuit, the voltage signal that passed the isolation transformer is subsequently filtered through a low-pass filter, consisting of a resistor R3 and capacitor C1. Finally, a Zener diode D1 prevented excessive voltage signal from flowing ...