Topic 4: Telephone Circuits

Topic 4: Telephone Circuits

Fig 1: Basic Telephone

Topic 4: Telephone Circuits

•Incoming Signaling•Answering, release•Outgoing signaling•Transmitter/ receiver circuits

Topic 4: Telephone Circuits

Fig 2: Incoming signaling circuit

Topic 4: Telephone Circuits

Fig 3: Answering Condition

Topic 4: Telephone Circuits

Fig 4: Outgoing signaling condition

Topic 4: Telephone Circuits

Fig 5: DTMF frequencies and keypad layout

Topic 4: Telephone Circuits

Fig 6: Simplified block diagram of telephone speech circuits