CHAPTER 12. Error! Use the Home tab to apply 제목 1,장 제목 1 to the text that you want to appear here.2-58 © SAMSUNG Electronics Co., Ltd.2.6.1.2 Block Diagram of Door PhoneThe block diagram of the door phone, which is used, connected to the OfficeServ 7100system, OfficeServ 7100, is as follows:Figure 2.34 Block Diagram of Door Phone2.6.1.3 Main FunctionThe main function of the DPIM is as follows:Micro-controller Unit (MCU)The signal transmitted from the DPIM PCM digital transfer part is conversed into theanalogue signal in HFC(High Feature CODEC). At this time, TL084 whose audio quality isgood is used as an amplifier to amplify the analogue signal, which was transmitted from thedoor box, and the displayed signal. Since the input resistance of TL084 should be great,100 kΩ is used as an input resistance.In the matching part, T5692 is used along with the trans of the door box. The resistance of1 kΩ(R14) is the resistance value when two trans have the best quality of transfer.Also, since the resistance of 100 kΩ(R9, R10) uses the signals transmitted and receivedfrom/to the trans by mixing them, it is a balance resistance for decreasing the input of thesignals, which are transmitted to the speaker, to the micro input of the HFC(NO. 19. pin).Door Lock Control PartIn the DPIM, the locker, which provides a function to open the door to a visitor, can bemounted. The general locker uses AC 100 V, which is turned on/off by using a relay as aswitch. At this time, the relay control port of the MCU is P10(No. 48 pin), and this port isthe key scan port in a digital phone. The diode of the relay control TR.(MMBT 2222, Q1)output end(1N4148,D6) is used to clear the counter electro-motive force. The cap and theresistance of the both ends of the relay are for preventing the spark occurring at the relaycontact.DPIM InterfaceMIC InterfaceSPK Interface
