Jack plugs are used as connectors. To distinguish it from the other jacks, the Mic-In jack is color-coded in pink.
Since certain microphones, such as the electrodynamic plunger coil microphones, only output voltages of 1 mV/ Pa or less, this must first be amplified in a microphone preamplifier before it can be used elsewhere. Appropriate preamplifiers with gains of 20 dB and more are available on sound cards. Other microphones like condenser microphones or electret micro phones produce much higher voltages, reaching about 50 mV/Pa. The input impedance is about 600 ohms.