Sistem Telepon Pertemuan 11 Matakuliah: H0122 / Dasar Telekomunikasi Tahun: 2008

Bina Nusantara 2 Mahasiswa dapat menunjukkan konsep telepon, bagaimana koneksinya serta masalah yang ada pada sistem telepon. Learning Outcomes

Bina Nusantara 3 Terminology Central Office Switching Outline Materi

Bina Nusantara 4 Terminology – Local loop – Central office – Exchange – Trunk – Nodes – Super trunks – Tandem switch – Hierarchy Telephone System

Bina Nusantara 5 Three major components: – Local loops: twisted pair, analog signaling – Trunks: fiber optics or microwave, mostly digital – Switching offices Local Loop End Office Trunk Toll OfficeSwitching Office Intertoll Trunk Components

Bina Nusantara 6 Hierarchy

Bina Nusantara 7 Telephone Terminal – Local loop and Basic Phone – Calling sequence in phone Talking signals – Analog voltage Outgoing : 1 – 2 V at approx. 3 mA Incoming : half of outgoing signals Local loop characteristics – Envelope delay – Voice grade: Dial-up or switched line Dedicated, conditioned or leased line Terminal/Local Loop

Bina Nusantara 8 Loop signal level – Outgoing : - 10 and 0 dBm (600  ) – Incoming : - 42 to – 4 dBm – Termination on the Central office : 600  (or 900  ) Dialing – Pulse – Tone Dual-tone multi-frequency (DTMF) Terminal/Local Loop

Bina Nusantara 9 DTMF tones for each number Terminal/Local Loop

Bina Nusantara 10 BORSHT is the function of Subscriber loop interface circuit (SLIC) or line card in interfacing to a local loop – Battery : - 48 V dc – Over voltage : protection from excessive voltage – Ring trip : send 90 V 20 Hz ac signal with on hook : 2 s ; off hook : 4 s – Supervision : monitor the phone loop – Hybrid: Two-wire to four-wire converter or four wire terminating set: plit the local loop into 2 wire pairs. Trans-hybrid loss: – 30 to 50 dB of rejection – Test To test signals on the line and to check quality of loop and phone performance Loop Supervision

Bina Nusantara 11 Process calling : – Recognize the dialed digits – Make physical connection Connection : – Allow an analog signal voltage – Switching systems in matrix (crossbar or cross point switch) – For greater reliability used reed relay Central Office

Bina Nusantara 12 Common Channel Signaling

Bina Nusantara 13 Echo parameters: – Signal travel time and travel distance – Echo time = (distance/prop.velocity) x 2 To Cancel – Insert the reverse path loss Echo suppression by insertion of reverse path loss – Signal subtractions Echo suppression using the signal subtraction method – Digital signal processing New version of subtraction method, need arithmetic calculation (algorithm) – Four-wire method Echo Cancellation

Bina Nusantara 14 Echo Cancellation

Bina Nusantara 15 Four Wire

Bina Nusantara 16 Telah dipelajari gambaran umum sistem telepon. Telah dipelajari komponen telepon. Summary